Hello,
i am at my wits end. The white chiffon rose of Sharon that i grew from seed is suddenly dying on me.
It was nice and healthy just a week ago, and suddenly i noticed that the leaves are yellowing all around. I’ve polled the internet for answers but they do not fit.
The leaves are not partially yellow, rather they first become a slightly pale green, then develop yellow tinge on the whole leaf, and then become almost bright light yellow. Almost the whole shrub is affected but seems like it started from the bottom.
it still has lots of flowers and buds on it, but the leaves are almost all yellowing.
I checked for bugs on the leaves, and could not find anything. there are no signs of any bugs or mildew on the leaves.
Please help. I can send some pictures if necessary.
I live in Thornhill, 1 km north of Steeles ave.
Thank you
The most common case of their leaves yellowing is poor drainage / over watering. Since you say that the yellowing occurred just about a week ago and the plant was healthy previously, I do suspect that the deluge we received on July 16th may have prompted this change. Is the soil under this plant still soggy? Is there good drainage in that area?” If the soil has dried out now, it’s possible that there will be no more yellowing. Dig down about 6 inches and see if the soil is wet, just damp, or dry. If just damp, that’s fine. If dry, then please make sure you are watering regularly. This heat wave is having a negative impact on our plants.
You say that you didn’t see signs of insects, but I wonder if you noticed some reddish pustules on the bottom of the leaves. The leaf at the front of the photo seems not to have any, but perhaps others do?
As explained by the Texas A&M AgriLife Extension Service, Rose of Sharon can be infected with Leaf Rust (fungus – Kuehneola malvicola) which does cause leaf yellowing. It is unlikely to kill the shrub, but you must cut back infected parts and destroy them. Do not put them in the compost. Clean up the area very well, since it can overwinter in the soil and plant debris.
Finally, the Morton Arboretum has an excellent discussion of chlorosis in trees. The glimpsed leaf at the back of the photo looks as though the veins are darker than the surrounding tissue, which might indicate a nutrition-based chlorosis. Conversely to my first comment, if water drains off the area very quickly, it is possible that soil nutrients have been washed away, and the Morton advice will be helpful.
I hope this has helped you to diagnose and solve your yellowing leaf problem. The plant looks strong and healthy otherwise, so I think that you may be able to resolve it without much further damage.
You might find our Gardening Guide to growing shrubs useful in general.