Syringa Ludwig Spaethe standard lilac


I have 3 Syringa Ludwig standard lilac trees in my garden. They are 5 years old and bloom every year. This year, 2 are blooming but one is not. It has small buds, which are green inside, and the twigs are green, but the leaves haven’t come. What can I do? Is it sick or just really late. Thanks


Elaine Johnson 19/05/22

It may just be slow due to the unseasonably cool spring however it could have a Lilac Bacterial Blight. Lugwig Spathe lilacs are one of the lilac varieties that are susceptible to this blight especially if weakened by things such as frost damage, accidental wounds etc. There is a detailed explanation about this blight on the Oregon State University site.     “The disease starts as brown spots on stems and leaves of young shoots as they develop in early spring. A yellow halo may also be around the spot. Spots become black and grow rapidly, especially during rainy periods. ” Take a good look at your tree to see if it has any the the symptoms listed. If it does have these symptoms, check the other trees as well.

As they recommend in the web site above: “prune and burn all infected parts as soon as you notice them. A spray of copper sulfate during the early spring each year should help prevent the problem before the buds begin to break.” Since it is still early in the spring, and the buds haven’t broken, you could spray it now. Since the other two trees have already bloomed, they cannot be sprayed until next spring if required. Your local nursery should have copper sulfate spray.