Or if you don't like the idea of potting it up.
Aug 27, S. reticulata the tree lilac, is also susceptible. Whether specific cultivars are affected more than others is unknown mainly because most people don't know the cultivar. Affected plants are reportedly mature and have"never been a problem" before this year.
Symptoms: Leaves turn yellow, then brown, and then shrubfall.clubg: Durham CA. Jul 05, I don't think that the holes in the leaves are necessarily related to the drooping and drying up, those could be related to cultural problems resulting from how the lilac was planted, or could be a fungal infection of some shrubfall.clubg: Durham CA.
Aug 24, Over the last few days, the leaves on one side of the plant (about a third of the plant) have dried up and turned a light brown color making that part of the plant look dead.

The plant has lost over half its leaves, and they're still falling. We had a very wet spring here, but it's been very dry for the last three weeks. The lilac is getting watered once a week with about 1" of shrubfall.clubg: Durham CA. transplanted lilac leaves drooping.
Yesterday I planted a large (3ft high) Lilac I bought at a nursery. It was in full flower at the nursery, in a large burlap root ball. I cut off the burlap, planted it in a large hole with good soil, watered deeply. The soil in the root ball was clay, and some of it broke off during the transplant, and I'm Missing: Durham CA.
Mar 31, Your bush might have a bacterial plant disease called lilac blight. A cool, wet, rainy, spring season favors development of lilac blight, especially if rains follow a late frost or winter injury.
Oregon State University Extension plant pathologists are Missing: Durham CA. Snout-headed, grayish-brown Fuller rose beetles look like miniature rhinoceroses. The bulging-eyed insects target lilacs' leaves and flowers. Ragged notches along leaf edges or entire leaves Missing: Durham CA.