I have a white (hardware store variety) rose. In early August, the leaves started to to loose its colour. While the veins and stems remained green, the rest of the leaf was a very very pale green to the degree that it was almost white. However, I do not think that it was powdery mildew as when rubbed between my finger and thumb, nothing was removed as evident on my fingers or thumb.
What there a nutritional deficiency or some other explanation? Thanks!
Pale yellow to nearly white foliage with green veins is likely related to iron or possibly a manganese deficiency, with a variety of possible causes such as: high pH (roses prefer slightly acidic 7-6.5 pH soil), too much water or poor drainage, to name a few. Adding iron chelate will help correct the problem, along with considering all cultural practices mentioned earlier.
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