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Gardening Area => Growing questions and answers => Topic started by: Saros on November 11, 2013, 09:17:35 PM

Title: Temperatures & plants. How low can it go? (Community research thread)
Post by: Saros on November 11, 2013, 09:17:35 PM
After talking about growing experiences with some other member, I think it would be great to compile a list of Seedian's experiences with various plants and what minimum temperatures that have survived (or died from). I'm not quite sure how I'll organize this yet but since we're getting into the cold season here in the States, I thought it would be a good idea to get this thread started so we can start adding info to it.

Personally, I'm leaving some sacrificial plants out in my unheated greenhouse this winter to see at what point they die. I'm using this temperature logger (http://dx.com/p/1-3-lcd-usb-temperature-and-humidity-data-logger-1-x-cr2032-71121) to keep track of the temperature inside the greenhouse. ***I can't seem to get this logger to work on Windows 7 for some reason***

The "Temp (C)" column is meant to be the lowest minimum temperature reached in that particular environment. For the plants in my greenhouse, it's the minimum temp that the greenhouse reached and maintained for any significant amount of time. If they're outdoor plants, I try to go by the actual minimum temperature reached outside rather than the theoretical zone minimum because some years, it doesn't get close.

The "Hours" column is meant to be how long the plant was exposed to those temperatures.

I think adding any other details about environment would be useful. So if you have any additional information that might be relevant to the plant's survival (or demise), by all means, include it. I'm in favor of collecting as much data as possible even though it's going to be a challenge to display it all.

If anyone wishes to submit data anonymously for 'naughty plants', please PM me with the info and I won't include your name with the data.

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Botanical NameLived/DiedTemp. (C)HoursAgeZoneEnvironmentUser
Acacia acuminataLived-866AUnder coverprasada
Acacia acuminataLived-566AOutdoorsprasada
Acacia acuminataLived-366AOutdoorsprasada
Acacia acuminataLived-3.36<1yr6BUnheated greenhouseSaros
Acacia maideniiLived-98AOutdoorscunningplatypus
Acacia simplexLived08OutdoorsGreentoe
Acacia simplexDied-68OutdoorsGreentoe
Agave paryiiTBD-23happyconcafeSevere damage (mushy leaves), Probably died
Alicia anisopetalaDied-68OutdoorsGreentoe
Alicia anisopetalaLived08OutdoorsGreentoe
Anadenanthera peregrinaLived08<1yr6BUnheated greenhouseSaros
Anadenanthera peregrinaDied-28<1yr6BUnheated greenhouseSarosLeaves stopped opening/closing.
Anadenanthera sp.Died-98AOutdoorscunningplatypus
Argyria nervosaLived-28<1yr6BUnheated greenhouseSarosDropped leaves
Argyria nervosaLived08<1yr6BUnheated greenhouseSaros
AriocarpusLived2.2OutdoorsNew Wisdom
Artemisia absinthiumLived-98AOutdoorscunningplatypus
Asimina trilobaLived-9<1yr6BOutdoorsSaros
Banisteriopsis caapiLived12.78OutdoorsFrog PajamasSigns of cold damage
Banisteriopsis caapiLived7.28Outdoorsmarshmellow
Banisteriopsis caapi (Cielo)Lived1.681yr6BOutdoorsSarosSlight drooping to leaves. Soil was also dry, so that may have been the cold or lack of water.
Banisteriopsis caapi (Cielo)Lived28<1yr6BUnheated greenhouseSaros
Banisteriopsis caapi (Red)Lived281yr6BUnheated greenhouseSaros
Banisteriopsis caapi (White)Lived1.681yr6BOutdoorsSaros
BrugmansiaLived7.77OutdoorsGreentoeIn ground, died back to roots
Brugmansia sp.Died-98AOutdoorscunningplatypus
Calea zacatechichiDied-98AOutdoorscunningplatypus
Calea zacatechichiLived1.6<1yr6BOutdoorsSaros
Centella asiaticaLived-98AOutdoorscunningplatypus
Desfontainia spinosaLived-98AOutdoorscunningplatypus
Heimia salicifoliaLived-98AOutdoorscunningplatypus
Heimia salicifoliaLived-68<1yr6BUnheated greenhouseSarosDied back to roots
Heimia salicifoliaLived-181yr6BUnheated greenhouseSarosDied back to roots. Leafs re-emerged 4/10
Ilex paraguariensisLived-98AOutdoorscunningplatypusDied back to roots
Iochroma australeLived-98AOutdoorscunningplatypusDied back to roots, regrew quickly
Leonitis leonurusDied-68OutdoorsGreentoe
Leonitis leonurusLived08OutdoorsGreentoe
LophophoraLived2.2OutdoorsNew Wisdom
MammillariaLived2.2OutdoorsNew Wisdom
Melaleuca alternifoliaLived-98AOutdoorscunningplatypus
Mimosa hostilisLived2129BUnder coverMadPlanter
Mimosa hostilisLived49BOutdoorsMadPlanter
Mimosa hostilisDied-581yr6BUnheated greenhouseSarosDropped most of it's leaves
Mimosa hostilisLived-281yr6BUnheated greenhouseSarosLeaves stopped opening/closing, but bounced back after 1wk indoors.
Mimosa hostilisLived081yr6BUnheated greenhouseSaros
Mimosa hostilisLived1.682yr6BOutdoorsSaros
Mitragyna speciosaDied-98AOutdoorscunningplatypus
Monarda didymaLived-18<1yr6BOutdoorsSarosDied back to roots mostly. A few tiny leaves around base stayed green.
MutucanaLived2.2OutdoorsNew Wisdom
MyrtillocactusLived2.2OutdoorsNew Wisdom
NeoporteriaLived2.2OutdoorsNew Wisdom
Nicotiana alataLived-26<1yr6BOutdoorsSaros
Nicotina rusticaLived-98AOutdoorscunningplatypusDied back to roots
OpuntiaLived2.2OutdoorsNew Wisdom
Passiflora caeruleaLived-581yr6BUnheated greenhouseSaros
Passiflora caeruleaLived-1881yr6BUnheated greenhouseSarosDied back to roots.. It was in a pot sitting in the corner of a raised bed in my greenhouse. Last year it grew roots through the bottom of the pot and firmly planted itself in the bed. The potted portion of the plant died during the winter. I thought the whole plant died until I noticed passiflora growing out of the complete opposite side of the bed. Apparently it lived on under the soil in the bed and came back from the roots.
Peganum harmalaLived-188<1yr6BUnheated greenhouseSaros
Phalaris aquatica (AQ1)Lived-3.3<1yr6BOutdoorsSaros
Phalaris aquatica (AQ1)Lived-188<1yr6BUnheated greenhouseSaros
Phalaris arundinacea (Big Medicine)Lived-3.3Under coverPermieGing
Phalaris arundinacea (Big Medicine)Lived-188<1yr6BUnheated greenhouseSaros
Phalaris arundinacea (Yugo Red)Lived-3.38<1yr6BUnheated greenhouseSaros
PolaskiaLived2.2OutdoorsNew Wisdom
Psychotria "nexus"Lived108OutdoorsSunshine
Psychotria albaLived-68OutdoorsGreentoeDied back to roots.
Psychotria albaLived08OutdoorsGreentoe
Psychotria albaLived7.28Outdoorsmarshmellow
Psychotria albaDied-58<1yr6BUnheated greenhouseSaros
Psychotria albaLived08<1yr6BUnheated greenhouseSaros
Psychotria viridisTBD108OutdoorsSunshineExtensive cold damage to 8" juvenile plant
Punica granatumLived-98AOutdoorscunningplatypusHawaiian seed
Punica granatum var. nanaLived-682yr6BUnheated greenhouseSaros
Salvia divinorumDied-98AOutdoorscunningplatypus
Salvia Divinorum (bunnell)Died-2.2OutdoorsSeed Collector
Salvia Divinorum (la fuerza)Lived28<1yr6BUnheated greenhouseSaros
Salvia Divinorum (la fuerza)Lived1.681yr6BOutdoorsSaros
Silene capensisLived-17.87AOutdoorsAuxin
Silene capensisLived-18<1yr6BUnheated greenhouseSaros
TephrocactusLived2.2OutdoorsNew Wisdom
TrichocereusLived/Died-98AOutdoorscunningplatypusIn ground. wet winter. living cactus developed tip rot but bounced back in the spring.
TrichocereusLived2.2OutdoorsNew Wisdom
Trichocereus bridgessii Lived7.77OutdoorsGreentoe
Trichocereus candicansLived7.77OutdoorsGreentoe
Trichocereus glaucasDied-12.78AOutdoorsAuxin3 day cold spell of -13.3, -12.7 , -12.2C weather. Froze solid.
Trichocereus macrogonusDied-12.78AOutdoorsAuxin3 day cold spell of -13.3, -12.7 , -12.2C weather. Froze solid.
Trichocereus pachanoiLived7.77OutdoorsGreentoe
Trichocereus peruvianusLived7.77OutdoorsGreentoe
Trichocereus terscheckiiLived-12.288AOutdoorsAuxinRepeated nights at -6.6C
Trichocereus terscheckiiDied-12.78AOutdoorsAuxin3 day cold spell of -13.3, -12.7 , -12.2C weather. Froze solid.
Voacanga africanaLived08<1yr6BUnheated greenhouseSaros
Voacanga africanaDied-58<1yr6BUnheated greenhouseSarosLeaves curled and froze solid
Title: Re: What survives at what minimum temperatures?
Post by: Mandrake on November 11, 2013, 09:31:27 PM
A reference guide for plant hardiness in regards to temperature would be very useful. Most of us have wondered whether one plant could be safely left outside during the winter, or whether we should plant it outdoors at all. I'd surely look forward to resolve these issues with a data list and a thermometer.

Both information sourced in good literature and personal experimentation, specially around valuable plants for the community, will be very welcome.

Thank you for the thread,

Mandrake
Title: Re: What survives at what minimum temperatures?
Post by: Sunshine on November 11, 2013, 09:39:41 PM
I just set one of my rooted la fuerza salvia cutting outside, out of the wind. It is around 4 inches tall. The current temperature is 47F and the time is 3:37pm. I'll update if anything changes.
Title: Re: What survives at what minimum temperatures?
Post by: Saros on November 11, 2013, 09:54:55 PM
It might also be useful to make note of how long the cold temperatures last when possible.

I suspect that one of the reasons my Heimia s. survived all winter long in the unheated greenhouse was because the lowest temperatures didn't last more than 8 hours or so. After sundown, the temps slowly drop until it just about equalizes with the outdoor air. Then as soon as the sun hits it in the morning, it quickly heats up again. If it didn't jump back up above freezing each day, I'm not so sure they would have had the same survival rate.
Title: Re: What survives at what minimum temperatures?
Post by: MadPlanter on November 11, 2013, 10:51:34 PM
The mimosa hostilis I have here have survived multiple days of straight exposure to 40F or slightly lower at night. I do however bring them at least under cover at below 35F. Maybe they could handle it but I just am afraid to hurt them.
Title: Re: What survives at what minimum temperatures?
Post by: cunningplatypus on November 11, 2013, 10:54:12 PM
Saros,

An excellent question! I've also been experimenting to see what manages to hang on through the winter. I've taken some casualties, but it's all in the name of science. 

I live in the Pacific northwest, zone 8a (minimum temps 10 to 15 degrees Fahrenheit). Winters are very wet.

Here are some success stories for me from last winter, as well as some failures. Everything was in-ground, exposed to the elements.

Success in hardiness zone 8a

Iochroma australe (died back to the roots, regrew quickly)
Ilex paraguariensis (Yerba mate. Died back to its roots, which is not ideal for slow-growing, foliage-valued plants)
Heimia salicifolia (Sinicuichi)
Melaleuca alternifolia (Ti Tree)
Acacia maidenii
Punica granatum (Pomegranate, Hawaiian seed)
Centella asiatica (Gotu kola, one of the varieties)
Artemisia absinthium (Wormwood, no surprise)
Nicotina rustica (died back, but lived!)
Desfontainia spinosa

Failures

Salvia divinorum
Mitragyna speciosa (no surprise, really)
Calea zacatechichi
Anadenanthera sp.
Brugmansia sp.

Mixed success/failure would be my in-ground Trichocereus cacti.

They took the full rain assault all last winter, completely exposed to the elements. None died, but almost every one developed tip rot. They all recovered nicely, and pumped out the pups this summer.

This winter, I'm trying to overwinter in-ground...

Psidium cattleianum (Strawberry Guava)
Psychotria alba
Moringa oleifera (Drumstick Tree)
Silene capensis (Dream Root)
Withania somnifera (Ashwaganda)
Andrographis paniculata

I think there are a lot of variables that may make or break a plant's survival in marginal areas. Most importantly, I'd hazard that proper mulching might make the difference.   
Title: Re: What survives at what minimum temperatures?
Post by: Sunshine on November 11, 2013, 11:40:15 PM
Its been 2 hours. The temperature has dropped 3 degrees and it is now 44F. The plant looks fine. I'll leave it for a few more hours.
Title: Re: What survives at what minimum temperatures?
Post by: fairdinkumseeds on November 12, 2013, 01:05:05 AM
I don't have much cold weather gardening experience, (or plan on getting any if I can help it.) But was told by an "expert" friend that mulching with lawn clippings was a good way to protect plants from the heavy frost, so I rushed around and mulched all the seedling fruit trees in couple rows as there had been frost predicted a couple months after we first arrived.
We had a big frost (well big for here) and the ones without mulch, which I didn't end up getting done in time, only about 10%-20% got a bit of leaf damage, nothing serious, but the ones with a thick donut of lawn clipping only 60% lived, mostly the stonefruit, and they all got really hammered, looked crook and died back. Same plants in both lots of rows, same open flat ground. Various guavas, custard apple, jackfruit, moringa, dates and stone fruit mostly.
I think the steam from the fresh leaf matter caused more ice on the roots and trunk? Whatever was the cause, I don't recommend fresh lawn clippings! Wasn't happy at all.
I would have thought that the moisture would trap heat and take longer for the temp to drop, but now I reckon that dry is better for some reason. Maybe less conductivity?
Title: Re: What survives at what minimum temperatures?
Post by: Sunshine on November 12, 2013, 01:28:49 AM
Going on 4 hours and the temp hasn't dropped any in the last 2. Its still 44F and it looks fine. No doubt it would grow slower at temperatures this low. I don't think it would die though.
Title: Re: What survives at what minimum temperatures?
Post by: Auxin on November 12, 2013, 02:34:43 AM
Silene capensis survives semi-arid zone 7a winters without protection, mine are actually flowering again right now after the first frosts.
Title: Re: What survives at what minimum temperatures?
Post by: Saros on November 12, 2013, 03:32:13 AM
Auxin, that's great to hear. I suspected they would hang in there longer than most. Mine are blooming like crazy right now as well. Hopefully I'll have a bunch of seeds to share soon:)
Title: Re: What survives at what minimum temperatures?
Post by: PermieGing on November 12, 2013, 04:01:13 AM
Something that could inspire some scientific experimentation is putting some of these somewhat questionably cold hardy plants near lots of stone, like a stone wall or in the middle of a bunch of stones on the ground. The stones theoretically absorb solar heat and release when not exposed to the sun...

Food for thought
Title: Re: What survives at what minimum temperatures?
Post by: Sunshine on November 12, 2013, 04:40:45 AM
Its been 7 hours since I put it outside. It is now 43F. Its supposed to get down to 30F tonight so I'm going to bring it inside. We'll see tomorrow morning if the cold effected it.
Title: Re: What survives at what minimum temperatures?
Post by: prasada on November 12, 2013, 04:33:01 PM
 I took some readings of  Acacia Acuminatas last night . The predicted low was -4c.
  Used a digital thermometer with three probes, one in soil,one for inside ambient temp and one for outside ambient temp. The plants ,in pots ,have remained outside for light and temperature acclimation .

 At 8pm     soil temp= 41.3f/5.1c     at 3am  34.5f/1.3c   at 5am 32.7f/.38c    at 9am 31.1f/0.4c
indoor ambient air  =36.8f/2.7c                   30.9f/-0.5c               32.5f/0.27c              45.1f/7.2c
outdoor ambient temp35.3f/1.7c                 29.1f/-1.6c               27.6f/-2.4c               31.7f/-0.16c

 so it looks like soil temp went below freezing , but i would suspect there is still some latent heat coming out of the water as it changes state  from a liquid to solid, some components of the soil could be colder than the water.   This cant be compared to a plant in the ground that is buffered by the earth temp.
 Oh yea ,the plants look fine.
Title: Re: What survives at what minimum temperatures?
Post by: Saros on November 12, 2013, 07:27:39 PM
prasada, that's great to be able to get such detailed measurements. I need to get myself a thermometer for soil as well. That might be an interesting number to keep track of for this.
Title: Re: What survives at what minimum temperatures?
Post by: Saros on November 12, 2013, 09:43:48 PM
I'm trying to keep track of this data in a spreadsheet for now and will update the table on my original post as I make changes to the spreadsheet. I've added all the info we have so far and tried as best I could to fill in the gaps using zone info and historical weather data. So, please double check that I didn't make mistakes or any outrageous assumptions while filling in the gaps=) I figure this will be constantly changing as we gather more data.
Title: Re: What survives at what minimum temperatures?
Post by: PermieGing on November 12, 2013, 11:01:45 PM
Phalaris big medicine

I have it potted on my fromt porch out of a frostable area. However its snowing atm and has been frosting and below 32f many nights so far and its pulling through.

Ill update with more info once its interesting enough
Title: Re: What survives at what minimum temperatures?
Post by: Greentoe on November 13, 2013, 03:13:34 AM
It hasn't gotten very cold here yet this year so I haven't been able to get any new results yet, but I have something to add from pass winters.

I've been growing brugmansia outside for three years now. 7.77C is the lowest the temp has gotten in 2011 and 2012. The plants have lived through this. It probably didn't stay at that temp for more than a couple hours but they did survive. The first winter I had them outside I cut them down about 4 inches above the ground around the beginning of December and made a bunch of cuttings from them. The next spring the plants came back from the roots. Their was one in a pot that was left uncut. The top of the plant died, but it also came back from the roots.

The next winter I only cut back a couple of them and left most of them alone. They dropped their leaves a couple of branches shriveled up and died, but most of the plant above ground survived. This years they grew giant compared to the year before. Easily 8 ft some maybe even taller. They looked pretty nice.

I believe they can survive colder temps if you cut them back and mulch over the roots well. They will then grow back from the roots in the spring.

Also all of my trichocereus cacti have survived these same conditions outside in pots. I have bridgesii monstrose, candicans, pachanoi, and peruvianus that have all tolerated the winter outside here.
Title: Re: What survives at what minimum temperatures?
Post by: PermieGing on November 13, 2013, 03:46:59 PM
So it got to like 26F last night and the phalaris big med is fine on my front porch, but frost cant get to it where it is at currently. I plan on doing more experimenting and observing when i propagate it alot in the spring
Title: Re: What survives at what minimum temperatures?
Post by: Seed Collector on November 13, 2013, 04:31:56 PM
It got 28 degrees Fahrenheit here last night. It killed 2 Salvia divinorum plants of mine, Bunnell strain. (all that were outside died).

Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: Mandrake on November 13, 2013, 10:58:54 PM
Thank you everyone, and particularly to Saros for the good work. We're starting to compile a great resource here.

This thread is now moved and stickied in the Growing Questions and Answers (http://sharetheseeds.me/forum/index.php?board=18.0) section, in the Gardening Area.

Keep the data coming!

Cheers,

Mandrake
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: Greentoe on November 14, 2013, 02:31:41 AM
Well tonight I'm going to find out if alicia anisopetala can survive freezing temperatures. I went to cut one of my plants back and take it inside today and noticed one of the vines had grown roots where it was on the ground. I left the rooted section of vine outside. Have my fingers crossed that it'll make it.
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: Sunshine on November 14, 2013, 03:06:40 AM
I've read that the fully grown caapi species can survive near freezing temperatures quite well for short durations(overnight).
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: prasada on November 29, 2013, 07:21:12 PM
  Last saturday the temperature went down to -9c , the acacias were on an unheated  deck out of the wind.
The temp at the plants was -8c or colder all night, the soil went below freezing ,-2c. The plants look fine.
They have gone through at least three -5 nights and sub-zero days.I put them outside for some sun one day,
 forgot about them, and it snowed. Didnt seem to bother them either.
The only thing I've noticed is the tips look dry,but they did that indoors too.
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: Saros on November 29, 2013, 07:49:16 PM
Nice prasada. That seems to hold true with mine as well. It's been down to -5c in the greenhouse a few times and likely even lower for a short time. The acuminata seems unphased.

The top part of one Psychotria alba died back but the lower part of the plant is still alive.
Phalaris Big Med, Yugo Red, and AQ1 are all doing file
Passiflora caerulea is still untouched
The Heimia salicifolia is starting to drop some leaves (and grow smaller ones closer to the base and stem)
Syrian rue is still alive.
Silene Capensis is still flowering
The Mimosa hostilis & Anadenanthera peregrina have dropped most of their leaves now or what's left would probably come off with a vigorous shake. I'm not sure if they're still alive or just dormant at this stage.

So far the winter has claimed
1 Argyria nervosa at -2c
3 Voacanga africana at -5c
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: TBM on November 29, 2013, 08:27:59 PM
I accidentally left a window open overnight when I was visiting relatives for Thanksgiving, it got down to 30°F outside but I'm not really sure how cold it got inside the apartment (window was only open ~4"). All of my psychotria (viridis and alba) were killed from the cold; the rest of my plants appear to be unaffected, it seems it got just cold enough to kill the psychotria but not enough for anything else I'm growing to die... I guess it could've been worse :-\ It seems psychotria (at least while it's >1 year old) is quite sensitive to the cold.
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: Saros on November 29, 2013, 08:54:29 PM
Aw man, I'm sorry to hear that TBM. I did that too a couple months ago while the weather was unpredictable. I didn't loose anything from it but it was a pretty awful feeling when I realized what I did.

I think maybe another factor with your Psychotria was the shock of it... Having been in fairly favorable conditions indoors and then the sudden drop to near freezing temps might have just been too much of a change for them.  The ones that I have in my greenhouse were both started from leaf cuttings sometime around May, but they've been slowly acclimating to the lower temperatures with the change of seasons. Still, I'm half suspecting that they're zombie plants.. by all rights, they should be dead.. they just don't look like it yet.
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: PermieGing on November 29, 2013, 10:48:09 PM
My phalaris big medicine has survived to around 20F while under my front porch.

Somehow, my new aq1 and yugo red survived that temp when i left em out accidentally as well, for 1 night. I dont recommend it lol. It scared me.
The yugo red has like 5 blades and the aq1 maybe 25.
Crazy
I wont be letting it happen again until i have propagated them alot
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: Auxin on December 03, 2013, 07:45:01 PM
Trichocereus terscheckii, barely survives average zone 8a winter, maybe.

So I had heard this stated before and last year tried to test it. Last winter turned out abnormally warm for my area- lowest low of 10°F, a quarter of night lows were 20°, nearly all were below 30°. A Zone 8a winter, the three golf ball sized T. terscheckii 'Valle Fertil' seedlings I left out survived fine.
This year, on the same week as last years 10° low, we had a record 3 day cold spell of 8, 9, and 10° lows. Those same, now slightly bigger, seedlings and a typical curved spine T. terscheckii the size of a huge grapefruit all froze solid and died (as did two T. glaucas and a T. macrogonus, none of which I expected to survive anyway).

If zone 8a at least be ready to insulate terscheckiis for the coldest nights, if colder bring them in for sure.
Remember USDA zone is an average and any one winter can easily vary by two whole zone rankings.

(F-32)/1.8=C :P
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: happyconcacti on December 13, 2013, 08:25:16 PM
Agave paryii, severely damaged (mushy leaves), likely dead at -9°F (-23C)
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: Saros on December 28, 2013, 03:01:21 PM
This is interesting.. the HBWR that I thought died when it froze solid about a month ago, has come back to life.  It was sitting in a tray of water and the roots were literally encased in ice for about 12 hours. I declared it dead, but brought the pot inside anyway, I stuck it in the back of my closet where it was warm, dark, and it seemed to thoroughly dry out.. I even started harvesting the soil for other projects. Today I was doing just that, and I noticed a new leaf! Surprise Christmas gift from mother nature=)
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: Saros on January 07, 2014, 11:11:16 PM
Wow.. same thing happened with two Voacanga Africana. Even one that I attempted to pull out of the soil after I declared it dead. I snapped the stem and busted up some of the roots before I realized it wasn't going to just pull out easily and gave up. Now it's pushing up some fresh green shoots.

I'm impressed with their will to live=)
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: Greentoe on January 08, 2014, 04:25:27 AM
I found out Alicia anisopetala, acacia simplex, leonotis leonurus, and psychotria alba can all survive 0c, at least for a short period of time. When it dropped down to -6c last night and barely got above 0c today it appears to have killed most of them. I'm not certain if the acacia simex is dead or alive. It rained two days ago so the soil was still kind of moist now its frozen solid. I have taken it inside now and will see if it looks like it hanging onto life after it thaws out.
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: Saros on March 06, 2014, 12:12:01 AM
Just noticed your update Greentoe. Thanks, I've updated the chart. I took a guess at the hours the temperature held steady at 0C.. figured it was overnight, so I put 8 hours in that column. Your findings with P. alba hold true with what I found as well. I pronounced it dead at -5C.

How's the A. simplex doing?
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: Greentoe on March 07, 2014, 12:10:03 AM
The acacia simplex that was left outside died :'(. Luckily I have another one the same size and I think 7 more I started last year.
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: Saros on March 18, 2014, 10:37:20 PM
Wow, Syrian rue has surprised me. I left one for dead outside in my greenhouse over winter and I'm starting to see little green leafs emerging again. We got down to -18C at the lowest.

I didn't realize it, but apparently it can handle down to -20C if the soil is dry.. and it was.
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: Saros on March 31, 2014, 07:14:39 PM
It seems Phalaris AQ1 and Big Medicine did just fine down to -18C inside my greenhouse. The jury is still out on the patch I had outdoors that spent a significant amount of time under snow & ice..
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: Saros on April 11, 2014, 09:10:21 PM
Heimia Salicifolia is coming back! woohoo! I knew it was a tough plant but I honestly thought this winter would do them in. We had quite a few nights  of -18C in a row. All four of my plants are showing signs of new leaves emerging now :)
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: Saros on July 25, 2014, 11:07:19 PM
Here we are, well into summer, and I just noticed my Passiflora from last year (that I thought died over winter) has resurrected itself. Last year I had a potted Passiflora in a corner of the greenhouse. It grew really large and put some massive roots down through the bottom of the pot and into the raised bed that the pot was sitting in. Over the winter the potted portion of the plant died off and I ripped the pot free from the bed when it was apparent that it wasn't coming back. I thought it was dead & gone until last night while I was harvesting some beets, carrots, and kale and I noticed a scraggly little Passiflora vine growing out of the opposite end of the bed. Apparently when it escaped it's pot, it lived on in the raised bed:) 
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: Sunshine on October 04, 2014, 05:34:31 PM
I had my viridis and my nexus sitting on the porch for the past few nights. The nexus looks fine but my viridis seems to have suffered extensive damage. I'm hoping it pulls through.

Anyway, the lowest it's got the past few days was 50F(10C) so if anyone has viridis outside keep a close eye on the temps. Also, it is a juvenile plant, around 8 inches tall.
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: Frog Pajamas on October 04, 2014, 05:58:55 PM
Same here. My viridis and caapi were the first to show signs of cold damage, right around lows of 55 degrees Fahrenheit.
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: marshmellow on October 04, 2014, 06:51:47 PM
It got down tho 45F last night and all my b. caapis and p. Alba's were outside I didn't know it was getting that cold . put them in greenhouse this morning didn't see any damage yet but we will see.
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: Sunshine on October 05, 2014, 03:25:02 AM
Mine were at 50-55F lows for a few nights in the row...maybe 5 max.
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: New Wisdom on October 05, 2014, 08:03:44 AM
All my cacti survived outside at temps of 36 f the other night.  Trichocereus, lophophora, ariocarpus, myrtillocactus, polaskia, neoporteria, mammillaria, mutucana, tephrocactus, opuntia, ect ect ect....
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: Saros on October 07, 2014, 11:10:23 PM
Time to begin the great plant migration of 2014...
Everything has grown so much this past year. I fear that navigating my house for the next 6 months will be like exploring deep jungle=)
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: Sunshine on October 08, 2014, 02:08:41 AM
Update- both plants lost all of their leafs. I give it a 50/50 chance they will survive.
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: New Wisdom on October 08, 2014, 02:11:35 AM
Time to begin the great plant migration of 2014...
Everything has grown so much this past year. I fear that navigating my house for the next 6 months will be like exploring deep jungle=)

It's going to be like Bolivia, Chile, Argentina, Mexico, Texas, Peru, and Arizona in my house during the winter. Lol!
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: Greentoe on October 08, 2014, 04:12:06 AM
I meant to post an update on here a long time ago about last winter. Turns out the psychotria alba plants I thought died still had some life left in them. Above soil the plants appeared dead, but come spring they started growing back from the roots.

This winter I plan to find out if a more mature plant, with thick woody stems might fare better. If it goes deciduous and regrows leaves from the stem in spring I'm going to start putting them in the ground.
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: Saros on October 17, 2014, 01:46:23 PM
Nobody had a great suggestion to add an age column to the table so we can keep track of how well plants at different ages cope with cold. This will be useful information for the TEGG project.
So please make note of how old a particular plant is when reporting it's survival or mortality:)
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: Frog Pajamas on October 19, 2014, 05:39:10 PM
I accidentally left a 10 month old Mimosa Arenosa outside overnight last night, with a low temperature of 4-5C. It probably spent about 3 hours at the low, with another 7 or 8 hours under 10C.

It looks perfect this morning- no issues at all; I will update if it develops issues in the coming days. In my observation the arenosas are the most cold tolerant of the three mimosas.
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: Chicsa on February 07, 2015, 04:50:14 PM
2 Mimosa Hostillis outside in multiple mornings of 45*F-50 (~7*C-10*C) No Damage noticed 1 had some drooping today on just the top node, unknown if from cold.
Hawiian Baby Woodrose one morning of 45*f-50f no damage or stress noticed
2 Psychotria Vidiriis multiple mornings of 45f-50f no damage or stress noticed
Cielo B. Caapi multiple mornings of 45f-50f no damage or stress noticed
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: Frog Pajamas on March 21, 2015, 06:32:42 PM
Phalaris Arundinacea "Big Med:"

Left it outside all winter on a covered porch. Lows were in the 20's to 30's (farenheit) nightly for a few months and we had highs in the 20's and lows in the single digits for about 4 weeks. It looked dead all winter but started growing a couple weeks ago and has a ton of shoots now.

Definetly a possible seasonal grower for anyone with limited indoor lighting in a colder climate.
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: BubbleCat on March 24, 2015, 10:49:41 PM
I guess this doesnt mean I can put my 3 leaf Nervosa outside just because the temperatures dont hit 0C anymore ? isnt it :) I think it needs / wants to go out.

Tabernathe Iboga:

lacking options I had them both in temps as low as 10 C for werks, maybe months. I consider it a pass, they still can be seen in my grow log, only the one that I moved into 25 C really took off and does much better. But yeah 19 C is okay for a long time.
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: Greentoe on March 25, 2015, 05:20:44 PM
I left my Iboga in an unheated greenhouse over winter. It only stays a couple degrees warmer in there than it is outside. It survived freezing temperatures, at least for brief periods of time. It lost most of its leaves but now it's putting out new growth and looks like it has some flower buds on it too. I repotted it earlier today and was surprised to see just how many roots this one year plant has.
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: SoulGrower on March 25, 2015, 08:17:23 PM
This is pretty exciting!  It seems that there are a few species I was under the impression would simply not survive cold.. much less freezing.  There are now several reports which indicate these tropical plants can do quite well outside, in the ground:

T iboga        --> may survive brief freezing temps (likely deciduous outside it's natural environment)
M speciosa  --> same
M tenuiflora --> same
S divinorum --> may be ok with temps to the 30's (mid 20's with some protection i.e. covering with a sheet)

I was certainly under the impression that M speciosa really got damaged below 65F.  Kept mine in a hoop house this winter.  Gonna be too big for that next year.  It's going in the ground this week to see how it fairs in my subtropical climate (brief freezing temps every few years).

I've also noticed that sometimes fairly well established zones for certain plants just aren't always accurate.  In my area, there are quite a few mature landscape plants that literature say are only suitable for 11-12.  I'm right on a line for 9b-10a however.  I think you can plant species a zone or two outside your range, and sometimes get lucky.
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: MirlitonVine on April 14, 2015, 06:12:19 AM


I've also noticed that sometimes fairly well established zones for certain plants just aren't always accurate.  In my area, there are quite a few mature landscape plants that literature say are only suitable for 11-12.  I'm right on a line for 9b-10a however.  I think you can plant species a zone or two outside your range, and sometimes get lucky.

Totally agree. Many people it seems think these rules are set in stone. It's more complicated than that. Plant can adapt quite well. I live in the exact zone as you do, I have quite a few plants which conventional wisdom would say could not survive frost/ freezes, yet they do fine.

Check out my mimosa tenuiflora, growing in the ground, survived 3 or 4 frosts, and one hard freeze.

And my HBWR who was on the edge of my un-heated greenhouse, it dropped below 32 in there for shore, all it's leaves were fried. It was cold enough in there to kill all of my coleus plants, various mints and a plumeria.

One of my psychotrias was also in the same spot next to the wall, it stayed green. I thought this plant was an alba, but it's beginning to show the stipules now, so if it's a viritis that's even more awesome.

My caapi was also in the greenhouse for the hard freeze. I had just got it in the mail and if I would have known it was going to freeze inside the greenhouse, I would have brought it into the house. It's just fine, enjoying her new home.
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: BubbleCat on September 21, 2015, 07:26:46 PM
I am bringing the Voacanga in and thought I want to report on recent conditions. It germinated August 2014 and spend this year as a balkony plant. In recent nights it has lived through 10 Celcius and maybe slightly lower with no harm or anything. Growth isnt measurable anymore though. I dont want to push my luck and see how low it goes until there is first damage.
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: happyconcacti on November 18, 2015, 03:15:43 PM
Hi All,

We've had an abnormally cold start to winter. We've had 4 or 5 nights where temps dipped below freezing (29F was the lowest -1.6C)

Things doing just fine:
2ft t. terscheckii, no damage at all
2x 6ft. Acacia acuminata v. narrow phyllode, actually still growing at the tips, amazing!
2x 5ft. Acacia maidenii, not looking so great, phosphorous deficiency I think, but not seemingly affected by the freeze
bunches of PC pachanoi, no damage at all

The only thing that does look so good after the cold temps:
1x 3ft. mimosa hostilis, the leaves have all turned brown and mostly fallen off, the stems seem to be alive, hopefully comes back in the Spring

A note about terscheckii:
the cacti grower that I'm working for keeps telling me terscheckii handle the cold better than most other cacti he's grown, including the native saguaro. He really thinks that they'll do just fine in zone 7a and possibly a bit colder. And so far, it seems to be true.

Peace,
hcc
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: Chicsa on November 26, 2015, 06:51:37 PM
cold damage to young caapis noticed one night of 46*F and a 2nd night of 50*F (7am-8am is hour of lowest temp)
Larger caapi seemed uneffected as did the HBWR
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: oplopanax on January 07, 2016, 05:11:43 PM
My attempt to over winter Mimosa tenuiflora here in the PNW in a greenhouse failed, she made it though the first freeze just fine, but that only lasted for a few days and when I went to check on her after this last cold snap (about a week of below freezing temps, frozen ground outside & some snow) she looks pretty dead, the trunk does not scratch green.

One thing that I wish I had noticed was that all the water that I had in a big tub in the greenhouse to act as a heat sink had evaporated before or during this freeze, if I had refilled it maybe the plant would have survived.

On the other hand, mt entire Trichocereus collection did just fine in an uninsulated shed for the entirety of the freeze, all I did was put a heat lamp in there like the one I use for baby chickens. This is amazing since I have lost so many cacti in similar conditions minus the heat lamp, and the amount of heat it gives off seems negligible.
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: AcaciaAve on January 07, 2016, 08:42:42 PM
@oplopanax
I usually overwinter the Mimosas and Acacias indoors for the first year.

My Acacia Melanoxylon plants are over 8 feet and have taken 2 months of nearly freezing temperatures, often times dipping below freezing(-1C)
Also, it was the first time in my life I've seen snow on the foliage of an Acacia.
Wish I had my camera with me.
The Acacia Melanoxylon was sprouted in April 2014 and has been on windowsill and moved outside since March 2015.

The base is very woody and there does not seem to be any dead foliage yet.
This is exciting, I got my fingaz crossed that the plant will make it to Winter 2017
:)

Pictures:
1=Acacia Melanoxylon(plant 1)
2=Acacia Melanoxylon(plant 1)
3=Acacia Melanoxylon(plant 2, a bit smaller than plant 1)
4=Acacia Decurrens forming weird foliage. This has occurred a few times previously before freezing conditions...
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: oplopanax on January 07, 2016, 10:31:07 PM
Yeah, my  tiny little house is sooooo full of plants already, I decided to give it a shot. Fail. The Mimosa was over 5' and everything!

Congratulations on the Acacia! You have it planted in CA?
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: AcaciaAve on January 08, 2016, 12:28:31 AM
There are some in CA...
...but this one's in WA...
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: Ian Morris on January 08, 2016, 03:23:10 AM
Ill add pics this weekend but I have let a  pot of pereskiopsis remain outside this winter as an experiment.

It sits against a wall so it is sheltered some, but so far we have had many below freezing nights and even a recent dip into the high teens. 

All three primary stalks are doing fine and the only damage so far was on some of the branches of the stalk furthest from the wall. 
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: Mangrove on January 08, 2016, 07:46:18 AM
Most, if not all, of my potted chacruna leaves have survived without the need for an artificial humidity dome here in sunny FL for a good 6+ months. As long as the soil is kept well watered and they're kept outside, I've noticed they seem to survive as well as ever, and also tend to produce sprouts faster than when kept in a humidity dome/ziplock bag.

Also, a 4 inch tall, 4 month old Acacia Simplex has survived constant outside temps throughout the winter and is still healthy but is growing slower than it would warmer, tropical conditions. Will keep it outside, probably transplanting soon. Will keep updated as to whether it lives or dies as the season drags on towards spring.

Recently, winter has hit the state, sending temperatures down into the forties and high thirties at night. So far, not narry a Chacruna kept outdoors come cold or a heat wave has died; those which have shriveled up the most were those set in well-draining perlite/vermiculite-rich soil mixtures while those in miracle grow potting soil seldom shriveled up regardless of temperature. I will keep the community updated as January progresses.
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: Stonehenge on January 16, 2016, 12:01:57 AM
My e novos have survived temps in the 40's but if it gets to the low 40's I will take them in. My outdoor kratom has survived freezes. It dies back and then grow again from the base. My b caapi has done the same. A freeze will kill everything above ground except maybe the thickest part but by late summer its bigger than before.
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: Pflanzenfreund on May 19, 2016, 10:55:39 AM
Phalaris Arundinacea "Big Medecine"

I've planted outside in Garden, temp can go down here in winter to -15 C.
No problem at all, i need to pay attention that it got not to invasive.  :D

Love
Pflanzenfreund
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: Chicsa on July 17, 2016, 04:58:52 PM
USDA Hardiness zones

N. America
S. America
Europe
Africa
Australlia
Florida
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: FewTrueSeed on September 28, 2016, 03:40:35 AM
It reached just below freezing last night and several housplants took a beating even in the cold frame. Orchids, psychotria and caapi first to show dislike. Cofee did fine as did mitagrina and pereskiopsis.
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: bezevo on November 27, 2016, 08:44:44 PM
I am in zone 5 there are so many cool plants I just can't grow  .

it gets as low a -10f  to -20f  ,

my potted figs and cactus come inside and into a cod dark room  in basement for several months of winter .

but the plants that won't go dormant it's  more difficult .

Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: BubbleCat on November 27, 2016, 11:22:01 PM
So last year I was very concerned about my Hovenia Dulcis, it had serious mite issues in the summer, dropped all leaves prenmaturely and grew them back very late. So I decided to keep it warm indoors hoping for life. This year its bug free, about two years old and it didnt shed leaves yet, altho it hits freezing point at night. I expect it to shed the leaves as soon as it gets colder. Quick research showed its fine down to -20 or -30 C, once mature. I will see how the young plant does this winter, and I will keep track of the lowest temperaturwe it will ever hit.
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: XDX on December 12, 2016, 01:55:46 AM
so far this year i've let some guys sit out in the cold. im not too keen on letting them die, so cant give the LOWEST possible temps, but figured id note what im observing.

Botanical Name                         Lived/Died       Temp. (C)   Hours   Age     Zone   Environment

Acacia maidenii                           lived                     -2               8+       3-4yr?     8B        potted under cover

Brugmansia sanguinea                 lived                   0                 8+         4yr         8B        potted under cover
Brugmansia sp. "double white"     lived                   0                 8+         6yr         8B        potted under cover

Capsicum pubescens                   died                    0                 8+         1 & 2yr   8B       potted under cover
Iochroma australis                      lived                   0                 8+         2yr         8B        potted, under cover

Solandra sp.                              Lived                    -2                 8+         5yr        8B        potted, under cover

Trichocereus bridgesii                 lived                   -2               8+         3yr         8B        potted, under cover
Trichocereus pachanoi                lived                   -2               8+         3yr         8B        potted, under cover
Trichocereus sp. Bk????             lived                   -2                8+        4-5yr       8B        potted, under cover

so some more details: its been getting colder here, days are about 7C, nights have been dancing around 0C, with occasional dips down to bout -2C. been like this for a week or two. i think we had some precipitation last weekend, but i was out of town. the weather app said it was supposed to get down to -3C last week, but when i checked that morning, i think it was saying it was only round 0C still. this week it has deff gotten down a little lower, like -2C at least for a few hours most nights. last week, when the app said -3, i brought in the brugmansia capsicum and the iochroma. capsicum already have some fungus, not looking soo hot, but if they die, i think it will be the adjusting/spidermites indoors that will do them in, in their already weekend state. bruggies and iochroma have been stunted for at least a month, but dont show much signs of cold damage.
the cacti haven't been watered since probably September, so they're pretty dry. they seem okay. i did have a huge 6 footer and another 4 footer get a lil wet a few years ago, and temps in the -6-0C, and they froze, then melted when they thawed, drowned in their own goo. soo sad. really dont want that to happen again, so any tips on symptoms to look for to tell if they're not happy (before it too late!) would be appreciated.
the acacia seems to be loving it. its sprouting new leaves & phyllodes. i expect to have some warning of chlorosis/necrosis on young leaves when its getting too cold, am i correct? i don't mind some die back, but i feel so bad when i let plants die, especially the more mature they get.
Solandra has been fairly dormant as well. it does get some water drips on a few leaves, but the soils dry. i brought it indoors today cause i see the leaves starting to fade and wilt, especially the ones exposed to the water drips. says it was -2C last night.

so all of these plants have been outdoors under cover for a good week, some two weeks, with night temps down to -2-0C. cacti and acacia are still outside, everything else is indoors now. for cover, i have a few loose sliding glass doors that i lean on the side of the house and pile plants under. solandra was on front porch, getting drips from roof runoff.




Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: oplopanax on December 14, 2016, 01:52:03 AM
Hey folks-

This year I planted a small PC Trichocereus pachanoi in the ground in the garden. I also left an Acacia burkitii outside in a pot that I started just this year.

I flipped a pot upside down over the PC, the Acacia is out in the elements.

They have both been snowed on and been in temperatures down to 22F (-5.5 C) overnight several times. They are both still alive so far. The PC was frozen solid feeling & came out of it.
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: FewTrueSeed on January 21, 2017, 06:20:33 PM
Last year i planted P. Somniferum late with little attention to whether they germinated. I was surprised in the spring to find that they were not only germinated but growing rapidly. Even before the spinach started growing! This past fall i did a fifty foot row and even now after months of cold, some temps below zero degrees F, Zone 4, they seem to be doing ok. I dont remember where i acquired this seed, but i was under the impression that most somniferum is not this hardy.

Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: Gardener on May 06, 2017, 04:08:25 PM
Of all the great threads here, this one has been the most helpful for me. And I look forward to hearing more Acacia results from those, especially in zones 8 and colder. 

For now, I can say that Desmanthus leptolobus and Peganum harmala survived a 2016/2017 USDA zone 7 winter, both in the ground and unprotected.  Lowest temps were around -7C on a few nights, sustained for around 8 hours. The D.l. were about 6 months old, and the P.h. were mature root transplants. Of course, both dropped all foliage and went dormant, resprouting in April and February, respectively.
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: BubbleCat on October 03, 2017, 09:00:15 PM
Sally hit ~8 °C at night repeatedly this year and remained unharmed (not just alive). She is sheltered from strong wind. I guess thats somewhere about her limit and I will not try to push much further.
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: Auxin on December 09, 2017, 12:59:51 AM
Has anyone tried growing Withania somnifera as a perennial in zone 7a?
When I started growing ashwagandha sources either said zone 9+ or zone 10+ so I just ruled it out. Now I just noticed most sources have switched to saying zone 8+ so I'm wondering if heavy mulching and a big pot overturned to cover the stump could do it.
I've never had one survive winter, though I have repeatedly left small ones in the ground, fully exposed.
They are able to self seed in my garden.
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: jbz711 on December 12, 2017, 11:42:58 PM
Piper Methysticum Survived  Temp: 3C, 8 hours, in zone 8b, in the ground but uncovered
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: Chicsa on January 19, 2018, 05:08:35 AM
Mimosa Hostillis uncovered 1 night of 28F no damage (9b)

Acacia Confusa uncovered 1 night of 28F no damage (9b)

Trichocereus species (most of em) uncovered 1 night of 28F no damage (9b)

B. Caapi uncovered 1 night of 28F most of plant is dead (10a)

P. Viridis several nights below 40F lost 75% of leafs covered for 28f unknown how it fared. tonight will be 32f-33f as the low (10a)

V. Africana several nights below 40F lost all leafs covered for 28f unknown how it fared. tonight will be 32f-33f as the low (10b)

T. undulata several nights below 40F severe leaf damage covered for 28f unknown how it fared. tonight will be 32f-33f as the low (10b)

Salvia Divinorum uncovered 1 night of 28F appears dead (10a)

M. speciosa uncovered 1 night of 28F died to stem (10a)

e. novo uncovered several nights below 40f lost 90% of leafs covered for 28f unknown how it fared. tonight will be 32f-33f as the low (10b?)

P. Nexus several nights below 40F very little damage covered for 28f unknown how it fared. tonight will be 32f-33f as the low (9b?)

yopo (A peregrina) uncovered 1 night of 28F no damage (9b)

Vilca (a. colubrina) uncovered 1 night of 28F no damage (9a?)

p. poepegina uncovered 1 night of 28F appeared stressed, but minor damage. (10a?)

I had a record breaking low, I think I could still be 10a despite this cold temp, the average of my lows over the past 15-20 years has been 10a, but very clearly I can have a once in 20 year 9b winter, and very clearly to me several of my plants are higher zones than i previously thought. I listed the zones I believe these plants to reliably grow in without dieing. I can say the majority of damage on p. viridis however, was caused by a temp drop from 80F to 42F in a single day.
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: danzick on January 20, 2018, 07:26:55 AM
Nice summary Chicsa.  We got down to 32 F here.

E. novo in pots - minor leaf drop
E. novo in ground - no damage
Voacanga in pots - total leaf drop, but no stem damage
Voacanga in ground - 70-80% leaf drop, but no stem damage
A. simplex in pots - no damage
B. caapi (various) in pots - no damage
Trichocereus in pots - no damage
Phalaria macrocarpa - massive damage, probably all dead

Most of the pots are close to the house or in other protected areas from the wind.  I agree with Chicsa that a sudden temperature drop with associated cold wind, seems to be more damaging than the absolute temperature.  I've found this to be especially true with E. novo.  They can handle 32 F no problem if protected from wind.  Fortunately, I was able to drag most of my rarer stuff into the house. 
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: JayWise on January 20, 2018, 05:46:02 PM
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Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: JayWise on January 20, 2018, 05:49:13 PM
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Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: Chicsa on January 20, 2018, 06:11:13 PM
1 mimosa hostillis looks pretty harmed from the cold, 2 others don't bizzare to me as they are all in the same part of the yard, could be from wind damage i suppose, one is more exposed to the wind than others.

HBWR toasted from 1 night 28f 1 night 34F

2 p. viridis survived covered both 28f and 34f nights, survived fine. no damage, 1 in another part of the yard was fried
e. novos survived covered on both 28f and 34f fine. no damage
p. poepegiana is fried.
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: danzick on January 20, 2018, 07:53:16 PM
After 32 F for about 3-4 hours.


Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: danzick on January 20, 2018, 08:02:05 PM
V. africana, not so good, but ok.

Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: JayWise on January 20, 2018, 08:55:05 PM
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Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: Chicsa on January 21, 2018, 12:42:27 AM
my biggest mimosa looks like it has a ton of damge, i dont know the extent, it could be dead, meanwhile the other two are perfectly ok with no damage, i'm confused but happy 2 survived.
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: Chicsa on February 20, 2018, 01:35:48 AM
looks like nearly everything that was severely damaged is coming back. a look at some of the recovery.... as I'm in full spring it seems mid 80s daily
B. muricata
Kratom
E. Novo
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: poroporo on April 09, 2018, 07:07:00 AM
Exceptional thread.
Will try and record temps this year and in the future.
Have had snowfall on the following (all survived)

T. pach, peru, bridgesii
Brugmansia sanguinea
Artemisia sp
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: XDX on December 06, 2018, 06:45:20 AM
Alright folks, its freezing here... literally.
Its not officially winter yet, but it sure does feel like it! I'm getting a little nervous here...

The cacti and Acacia are still outside.  Its been getting colder steadily every night- in F, 33, 30, 28, 27. day temps have been in the 40s. tonight and tomorrow are supposed to get pretty chilly, says 25 tonight, 24 tomorrow. were breaching the record for these exact plants, i brought them in early last year because i left town for the holidays and wouldn't be around to monitor, and then there's data I posted about a page back in this same thread for Dec 2016, says they survived -2C or 28F for extended time.

I am being lazy, and debating leaving the plants outside. its just for a few hours, then temps will turn around and work back into the 40s. 10 day forecast says after these two nights, temps will bump back up to mid 30s at night, 40s still during the day.

the cacti got rained on pretty hard last month, but then it was dry for a bit, and i put them under cover before our last heavy storms. under cover is two sliding glass doors that are leaned against the S side of the shed, so get some sun (if there were any lol), but protected from rain. so its been 3-4 weeks since they've actually been watered, but the soil is still fairly damp. there are several ~5yr pachanoi and bridgesii, and one or two peruvianus, all from seed, and then one big BK "Chavin" clone about the same age, all with several pups. the tallest seedlings are ~1m tall, but some are a bit less,and with 5-10cm diameters. the BK is even bigger. then there's a few smaller maybe 2 yr old seedling hybrids and top cut clones, just under a 30cm tall with an 3cm or so diameter. all in pots

the Acacia maidenii is also i think 5 years old, its been stunted due to being topped and container culture, but its in a 25-30 gal (fake, plastic) half wine barrel, actual height of the plant from top of soil is ~1.5m now, with ~3-4cm trunk diameter at the base. it has not been under cover at all, and got rained on pretty heavily like 2 weeks ago. it got some rain last month as well, but in general, it has been relatively dry this year until recently, the heavy rains came late. also, i only watered it twice near the end of summer, before that it went probably 4 months in full sun without any watering or rain. the is a good 2-3cm layer of mulch that is pretty well established with some fungal mycelium as well, and it is possible that this may be generating some heat and thus keeping the root a little bit warmer.

normally, the Acacia starts to grow new leaves with the rain, and then the new growth freezes and dies back, and get scared and bring the thing in. this year, there is not a lot of super fresh growth, not yet at least, there are new phyllodes that popped up maybe a month or two ago, and they are small but seem hardened off. all phyllodes, old and young, are changing from a solid green (deep on mature, vivid on new), with maybe a few red tips, to more of yellowish pea green, nearly all with reddening edges and tips. its dark now, i should have been on this earlier and taken some pictures

what do you all think?? do i risk it for a biscuit (more like a tidbit of info), or do i call it now and bring everyone inside for the season? there's a lot of pots, some of them pretty good sized, its gonna take a bit of time and do my back in. but  i will be so sad if they all freeze to death, I've frozen a cacti before, it about broke my heart. but its only for a few hours... ahhhh!!
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: XDX on December 06, 2018, 08:20:12 PM
All is well in the world, everyone survived!
that was about 6 hours below freezing, with the low low of 25F
its low 40s now. supposed to drop about the same tonight.
I'm going to leave them out...

pics! i don't see any sign of cold damage, the tips don't look like they are suffering, even on the smallest of them.
oh, and check that block of ice out with the Phalaris, that is real.
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: FranxLove on October 30, 2019, 01:59:42 PM
Q: Do zone 10b cacti and Caapi need to be brought inside in winter because of the frosts?

Thank you.
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: ONandONandON on October 30, 2019, 08:11:53 PM
in same zone .. yes bring caapi inside before it hits the low 40s.
cacti outside in zone 10b survived last year.. couple cold weeks,
smaller seedlings should be kept away from the cold if possible.
some cactus are adapted to cold, some are warm weather cacti.
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: Chicsa on November 02, 2019, 01:50:59 PM
Caapi can survive down to the upper 20s... Also a z10b climate should never have frost as the minimum temperature of a 10b climate is 35F well above the frost temp. I'm in a 9b/10a climate, I never bring caapi or cacti in.
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: MadPlanter on November 02, 2019, 02:39:55 PM
I put my psychotria, Kratom, caapi, etc in a greenhouse like barn thing and it can definitely get freezing cold in there briefly a few times each year here. They seem to handle all good. Maybe wilt a bit but spring back by mid day. The iboga, noni, vanilla orchid, Novo, P. horizontalis, and red Borneo Kratom, cuban oregano are lessly tolerant so they come indoors on the coldest nights. My cactus collection does fine from the low 20s°F and up as long as not under open sky. Surprisingly dragon fruit handles well under an overhang too in that cold of weather.
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: Otorongo on November 08, 2019, 02:57:53 PM
Caapi can survive down to the upper 20s... Also a z10b climate should never have frost as the minimum temperature of a 10b climate is 35F well above the frost temp. I'm in a 9b/10a climate, I never bring caapi or cacti in.

It can get frost. USDA zones are determined based on long-term averages. So zone 10b doesn't mean it never gets below 35F, it means the average annual minimum is >= 35F and < 40F.

Also there is ground frost, air frost etc. Official temp readings are taken 2 meters above ground, closer to the ground it generally gets colder. And you may have frost pockets etc.

It looks like my caapi saw its first frost last night, 2 leaves are showing damage. I'm going to twine a soil warming cable around its base and lower stem, put it on a thermostat and fleece the vine soon.
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: arborescent on November 10, 2019, 05:23:47 PM
Wanted to report 3 adult Phalaris brachystachys plants survived 19F/-7.2C with minimal damage aside from some yellowed leaf blade tips. Grown outdoors, and has been slowly creeping below freezing at night the last two weeks or so.

It appears as though my P. aquatica AQ1 has survived mostly unscathed as well.
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: Otorongo on February 22, 2020, 07:22:31 PM
Acacia floribunda: -6C, no damage

Trichocereus peruvianus: -6C, no damage
Trichocereus bridgesii: -6C, no damage
Trichocereus pachanoi - some specimens survived -6C unscathed, some turned partially or completely into mush. Old, thick growth does better. Slug damage and rot seems to be a major factor in their survival

B. caapi - died in a winter that saw -2C. Probably due to the prolonged cold and wetness
P. alba - died in a winter that saw -3C or so
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: wanderer on March 29, 2020, 11:06:05 PM
Zone 7/8 Southeast US here (Atlanta area)
Plants in-ground and unprotected.
Many winter failures, but a couple of nice surprises:
Salvia divinorum usually regrows from the base in spring.
Acacia floribunda does well and is already flowering @ 2 years old.
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: RatsboggleBiological on September 11, 2020, 02:43:20 AM
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Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: MadPlanter on December 26, 2020, 03:42:32 PM
Could be too early to tell but it appears that so far at least my Kratom tree of around 7ft tall survived around 22°f only tucked back under the porch. Obviously the microclimated position under the porch may have been warmer by several degrees. However leaves not yet wilted and otherwise has not defoliated either. Would be awesome if in fact it remains that way after a few days. Will update if not.
Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: MadPlanter on December 26, 2020, 04:05:52 PM
Few other entries here.

Heimia salicifolia completely unscathed after completely exposed to the open sky on a 22°f night. In fact survived unscathed lower than that before around 18-19°f.

Some tropicals that freeze back but return in spring in our average zone 8b-9a winters are:
Sisso spinach completely unprotected
Longevity and Okinawa Spinach lightly or completely unprotected
Talinum species waterleaf and jewels of opar completely unprotected
Chaya lightly or completely unprotected
Cassava lightly or completely unprotected
Bananas completely unprotected
Sugarcane completely unprotected
Katuk completely unprotected
Sweet potato completely unprotected
Pineapple considerably protected
Thai guava completely unprotected
Strawberry guava lightly microclimated under porch
Ginger/turmeric family completely unprotected so long as not allowed to be soggy wet during these winter temps
Canna edulis completely unprotected
True arrowroot completely unprotected
Mexican sunflower lightly or completely unprotected Glycomis pentaphilla lightly protected

Title: Re: Temperatures & plants. How low can it go? (Community research thread)
Post by: Otorongo on March 28, 2021, 03:10:26 AM
To add to the acacia data:

Zone 9, -4C (25F) being last winter's minimum

Acacia retinodes - no damage
Acacia maidenii - was under horticultural fleece during the cold spell. Most leaves browned, some green remains. It has yet to resprout (or show it's not meant to)

The floribunda and baileyana (blue-ish, not purple) are fine yet again.

More tropicals that made it:
- Avocado (probably Hass) - was under fleece; topmost leaves browned; no stem damage
- Strawberry guava - under fleece during the cold spell; not only fine, but retained the fruit, which is ripening now
- Lemon guava - under fleece during the cold spell; minimal damage (leaf discoloration, but no necrosis)
- Citrus:
  * sudachi - no damage and retained its fruit, which is continuing to ripen
  * yuzu - no damage
  * calamondin - peripheral leaf damage, 95% ok
  * Citrus aurantium - ok
  * Meyer lemon - ok