Villosa Lilac turned brown

Credit: Stacey Newman/iStock

Q: I happened to notice that one of the trees in my Villosa lilac hedge had turned completely brown. The leaves were still soft, but they were all brown. Since then, I have noticed several of my specimen or nicer lilacs are starting to turn brown as well. Not all of them (and not the whole tree) but several definitely are. I have also noticed dead spots on my rose bushes. I had originally thought that someone had mowed too close, but that does not seem to be the case. Also, we have a row of very old Black Poplar right beside our house. I have noticed leaves falling onto the deck that seem to have been burnt on the tops of them. They are actually black. The under side does not seem affected. Earlier in the year my row of Saskatoons seem to have lost most of their leaves and I thought that it was due to underwatering. Now I am wondering if these are all connected. The year started out with
not much moisture but we have had adequate since July. HELP!!

There is inadequate information. All problems may not be related. The pictures are not conclusive. But nevertheless I will give it my best suggestion. I will concentrate on the lilac bush. Lilacs by nature require full sun. Good growth (at least 15 cm or 6 in.) is ideal for flowering since new growth is necessary for flowering. Soil which is well-drained but has a lot of organic matter, e.g. top-dressing, with good moisture but not soggy. Even soil moisture is essential especially during dry periods, e.g. good soaking at least once or twice a week if no appreciable rainfall. Lilacs resent excessive root competition from other plants, e.g. roots could twice as wide as the actual height of the plant. Leaf drop from poplar could be water stress enjoy boggy spots. Dead spot on rose could be “Blackspot” (fungal disease). “Saskatoon” (Amelanchier) require ample moisture, rich soil and are intolerant to stressed sites.