The Lilac Pruning Method That Helps Encourage New And Healthy Blooms

Knowing the best time to prune your lilacs is important for keeping the plant healthy. If you miss the timing, you can ruin next year's blooms or mess with the future growth of your lilac. Typically, you should be pruning your lilac bushes on a schedule. However, if your pruning schedule has been disrupted or never started in the first place, it might be time for a bolder, all-encompassing pruning method. This is especially true as bushes get overgrown or scraggly. If you have a lilac bush that has not had regular pruning, it may be necessary to use rejuvenation, or renovation, pruning.

Rejuvenation is different from regular pruning and should only be used for specific goals. In overgrown lilac bushes, the lower sections often lose leaves because branches become heavily shaded. The result is fewer blooms and the entire plant losing shape. Rejuvenation pruning is a way to encourage the development of new, healthy blooms on these kinds of overgrown bushes. 

To rejuvenate an older lilac bush, the entire plant needs to be cut back significantly. That means all of its branches should be cut down 6 to 8 inches from the ground. Sometimes the recommendations are even more aggressive, suggesting you cut the bush down to 4 inches above the ground. And, although lilacs are usually a popular plant to avoid pruning in winter for big spring blooms, rejuvenation pruning is best done in late winter or early spring. The resulting impact on a healthy plant should be the development of a lot of new shoots in the spring.

There are a few mistakes everyone makes when growing lilacs, and one you want to avoid with rejuvenation pruning is severely pruning a bush that lacks vigor. Lilac bushes can become stressed after major pruning, so rejuvenation pruning is best reserved for healthy plants. Another, less severe option if you are worried about the health of your older lilac is to rejuvenate over a longer period of time. You can develop a plan to cut down the oldest branches slowly over a three-year period. While this method takes longer, you also have the advantage of enjoying your lilac bush blooms each year, unlike with the other kind of rejuvenation pruning. When you cut down a lilac bush to a few inches above the ground, you will likely have a year or two without blooming.