How Do I Care for Lilac Trees?


Lilac trees are deciduous spring-blooming shrubs that have green leaves and clusters of sweet-smelling flowers in purple, pink or white. Caring for lilac trees is relatively easy. There are just a few steps to take to ensure you will have a tree that is full of the lovely blooms in the spring.

Care of Lilac Trees

Step 1

Scatter a few handfuls of bone meal around the base of an established lilac tree in early April when the leaves start to emerge. Do not let the bone meal touch the plant. Scratch it into the soil with a cultivator and water. If the tree is having trouble blooming, you may need to take a soil test. Home soil tests check the pH of the soil and can be found at any garden center. Follow the box instructions, and if the soil is acidic treat it with a little bit of garden lime dug into the soil around the tree.

Step 2

Cut off the blooms with garden shears right after the blooms start to fade. This will stop the tree from trying to produce seed. It is unnecessary for the tree to do this, and cutting off wilted blooms redirects energy into the growth of roots and branches. Cutting off the blooms also encourages new blooms to grow. Just cut the stems of the faded blooms right below the flower.

Step 3

Prune the lilac tree when necessary. These trees seldom need to be pruned. Take out all dead branches in spring before the tree blooms. Prune to shape the tree right after it stops blooming in May or early June and never later than the second week in June, because next year's blooms form on the tree prior to mid-June. If you cut any branches off after mid-June, your tree will not have any blooms next spring.

Step 4

Prune the tree back severely if you had few blooms on the tree. Lilacs need sunlight to thrive, and sometimes they grow so dense that they prevent sunlight from getting inside the branches. You may have blooms on the outside of the tree but none in the center, or you may have very few blooms. After blooming season, cut back each branch that is 1 1/2 inches in diameter or more one-third of its length. There may be limited blooms the following year, but the year after the tree should be full of blooms.

Tips and Warnings

  • Lilacs are not often affected by disease, but there is a bacterial blight that can attack during the first three or four years of growth. To prevent this, use a fertilizer that is not as high in nitrogen content. Lilacs are usually pest-free but can be affected by stem borers. You can identify the problem by the yellowing leaves and a bit of sawdust around the base of the tree in the winter and spring. Prune the damaged stems once the problem is identified.

Things You'll Need

  • Bone meal
  • Garden clippers
  • Hand cultivator
  • Soil test kit
  • General fertilizer for flowers
  • Garden lime


  • Garden Action: Lilac Tree Care and Pruning
  • Natures Best: Caring for Your Lilac Bushes
  • Lottah Nursery: Culture and Care of Lilac Bushes

Who Can Help

  • NDSU Extension Service: Questions on Lilacs
Keywords: Lilac care, Pruning lilacs, Making lilacs bloom