When Should You Prune Lilac Trees?

When Should You Prune Lilac Trees?

The National Gardening Association recommends pruning lilacs immediately after flowering. Removing broken and dead branches before trimming aids in achieving a desired shape and size. Stems longer than 2 inches should be trimmed; lilacs may be cut back by as much as one-third.

Applying a layer of compost and a 2-inch thick layer of mulch in the spring helps the lilac tree to retain moisture and discourages weed growth. While many lilacs are drought-resistant, summer weeks producing less than 1 inch of rainfall require adequate watering of the lilacs to ensure lively growth. Bushes do not need regular pruning until they are between 6 and 8 feet in height.