by Ken Lain, the mountain gardener
Young, immature plants rarely need pruning except to deadhead faded flowers or remove dead and broken branches. Once a lilac reaches a mature height, it appreciates rejuvenation pruning.
Young bushes with branched under three years old offer small flowers at best. Older branches, 5-8 years old, produce the most flowers. Branches older than 8 years in size should be thinned to rejuvenate your plant to younger, more vibrantly blooming branches.
When to Prune Lilac for Regular Maintenance
Lilacs are best pruned within two weeks after they finish blooming in spring. Lilacs form their spring flowers starting in summer that persist through winter for next spring blooms. Pruning other than late spring reduces next spring’s flowers. The shrub tolerates pruning almost any time of the year, but if you want better color, it is best to prune right after their spring flush.
STEP 1 Deadhead Faded Flowers from Your Lilac Bushes
Removing all shriveled blooms as they fade. To do so, find the first pair of leaves beneath a faded flower cluster and snip just above those leaves.
STEP 2 Remove Dead, Broken, Bug Infested, or Canes that Rub
Remove canes that appear damaged or infested with pests, such as the lilac borer. Borers appear as small holes at the bases of shoots, accompanied by sawdust. Where two canes are rubbing together, remove the weakest to prevent damage to the more vital branch.
STEP 3 Rejuvenate Your Bush by Prune 1/3 of Its Old Canes
Mature bushes over 8 years old require rejuvenation pruning. Prune 1/3 of the oldest, largest branches back to the bush’s base. This may require a pruning saw or bypass pruners.
STEP 4 Remove all suckers
Remove all shoots or suckers growing from the base or your lilac bush.
STEP 5 Rejuvenate Old Plants over 3 Years
Mature bushes over 8 years old need a 3-year rejuvenation periodically.
Remove another third of the old canes during the following spring, and repeat the process during the third spring season. Once all of the oldest growth has been cut out, allow the shrub to grow unchecked for 3 years, after which point you should repeat this rejuvenation process.
Spring = 7-4-4 All Purpose Food + Soil Sulfur
Summer = 7-4-4 All Purpose Food + Humic
September = 7-4-4 All Purpose Food
December = 7-4-4 All Purpose Food
Lilac Jelly – If you want a fun canning project in spring try Lisa’s Lilac Jelly Recipe.