I purchased two service berry trees several months ago and had them transplanted in a VERY shaded area of my yard. There is a another service berry tree there and it has done well so i thought having more of these would work. However, the new ones quickly developed powdery mildew and Sheridan told me to apply Defender. I removed all the badly infected leaves and have been spraying weekly but it appears that many leaves are yellowing and falling off and i am afraid i will have denuded trees before winter. Can you offer me any advice to encourage their healthy growth?
I attached a picture.
Thank you for contacting the Toronto Master Gardeners.
Service berries are native to Ontario, do best in full sun but will tolerate part shade. The berries are delicious and edible if you can get them before the birds. But you probably know this as these are not your first ones.
I can see that your service berries do not look well. I would suggest that you take them back to the provider and start new next year. Sheridan is reputable and probably has a refund policy. Check with them before you take this action. I suspect that either the original soil or plants were infected but cannot be sure because you did not provide details, such as a weekly diary.
The other alternative is that there was powdery mildew in your garden already.
Powdery mildew will come back yearly. The mildew lives on the fallen leaves and in the spring animals and rain re-infect the same spot. The humidity in the summer augments this problem. I suggest that you clean up the entire area this fall and then amend the soil with leaves and soil/compost.