Lilac Bacterial Blight: Brown-to-Black Leaves, Not Just Water Issues

Question about leaf color meanings: yellow=underwater, black=overwater, what does brown mean? Follow-up: lilac leaves/flowers browning after stopping water.

Clarification

Brown/black tips = overwatering. But lilac blight (Pseudomonas) causes brown blotches on new leaves in spring with cold/wet fluctuations, progressing to blackening, wilting, drop. Resembles fire blight.

Management

Wait for warmer weather, prune 6+ inches below infection. Disinfect tools (75% alcohol or 1:3 bleach). Remove/burn all cuttings. Avoid high-nitrogen spring fertilizer. Fall spray with copper fungicide (Microcop/Bordeaux). Repeat spring before bud break. Maintain open pruning for air circulation.

Follow-up

Don't stop watering completely—weekly deep soak if no rain. Atomic Grow may help restore health. Blight overwinters in diseased twigs.