If the tree is already infested, it must still be healthy enough to transport systemic insecticide through the trunk and into the branches and canopy in order for the treatment to be effective – if 50 ...

They are susceptible to powdery mildew, and a pesky insect, the lilac-ash borer, finds the plant as appealing as the pollinators do. If you live in regions that are often too warm for lilacs ...