by Amjad Qasem
Any clue why some parts of this lovely white rose tree are getting pale
the texture is healthy ,but the color is pale yellow
A long time ago, I decided not to try and grow roses, and this type of thing is why.
They are not the easiest plants to care for, and sometimes, despite providing exactly what we think they need, they will still fail to thrive.
One thing that I see on the leaves is a white powder, which could be powdery mildew.
This can grow even on leaves that are healthy and dry, and it's hard to get rid of.
One thing that does seem to help is to cut off the leaves that are affected, and get rid of them.
Never leave dead leaves anywhere near the plant, because the spores will float around and before you know it, it's back.
You can also try spraying with a teaspoon of Bicarbonate of Soda (baking soda, not baking powder) in a liter of water. This alters the pH of the surface of the leaves, preventing the powdery mildew from germinating.
In some cases, the leaves will turn yellow simply because they're old and worn out. Cut them off, it won't affect the plant.
Another reason for yellowing leaves, and a much more dire one, is virus. This plant doesn't appear to be suffering from that, but they are prone to it.
Typically, the leaves will be mottled in pale yellow and green, and the plant will not thrive. It's important to cull any plants like this, because the virus will spread easily, being carried by aphids and other pests.
Hope that helps,