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[BubbleCat]

Hey peeps,

so my Hovenia Dulcis is a strange display of chlorosis. It isnt yellow, but near perfecly white with very clear boundaries (1) and the veins remain green (2).

Now it is easy to assume malnutrition (Mg ?) but more often than not that is not correct, theres a myriad of causes for chlorosis, like drough, NaCl, heat and overexposure to sunlight, viral infections and so on ...
So I want to share this picture and ask you guys.

There is other discoloration too, like in the second picture, yellow, brown / redish and necrosis.

[BubbleCat]

Now the same issue on Passiflora. It is not shine / reflection, the leaf is white.

[ONandONandON]

very strange idk maybe a copper deficiency,  hah   
but seriously, being on two plants, it sounds like a lack or excess of nutrients.
Chlorosis is formed when leaves can not get nutrients to produce chlorophyll..
Excess of one nutrient can block another nutrient, so this is hard to diagnose.
The only thing i can think of todo is repot into fresh soil and hope for the best.

_+.

Chlorosis on cannab:
When white areas form at leaf tips or in between veins, the plant is Zinc deficient.
This can be treated by adding organic fertilizer containing Zinc or by burying galvanized nails in the soil.


Chlorosis on bushes:
• Waterlogged roots due to poor drainage
• Damaged and/or compacted roots
• Overuse or misuse of pesticides and/or herbicides which are commonly formulated to cause chlorosis in target weeds.
• A mineral deficiency in the soil. A lack (or excess) of potassium, zinc, iron, magnesium, etc. and/or proteins is probable.
Other, less likely causes include:
• Deficient nitrogen
• A high soil pH that prevents roots from absorbing minerals
• Exposure to sulphur dioxide
• Ozone injury to sensitive plants
• An attack by bacterial pathogens

[BubbleCat]

I sure know the possible causes for chlorosis, the only thing being: Most deficies that lead to chlorosis cause yellowing first and follow simple patterns. Depending on the mobility of the nutrients different leaves are affected, in most cases either all or young ones. Now I lean towards an infection or radiation burn because I can not determine such pattern. I might add to the description to the issue that it doesnt affect leaves of certain age, young ones look good, old ones look good, at random some look bad. Adding to my amazement is that I've never seen chlorosis that spontaneous and being perfecly white. I may suggest it is caused by sudden onset of very sunny day or nighttime temperatures sometimes dropping below 5 C. But I can riddle alot, I wonder if someone knows for certain.

[BubbleCat]

So I put some research into my dominant suspicion and I do feel like it is a manifestation of sunburn.