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Care of Lilac Trees

By S.F. Heron ; Updated September 21, 2017
Healthy lilac flower.

Springtime brings a fragrance to the air unlike any other during this time of year. Lilacs offer an outdoor perfume that scent the air with a sweet, gentle reminder that summer isn't too far away. Lilac trees or bushes offer stunning purple or white blooms on a handsome plant with large leaves. These hardy perennials require some care to keep the plant blooming for multiple years. Let's look at how to take care of lilac trees, so your plant can grow into a stunning focal point in your landscape.

Care of Lilac Trees

Evaluate the current situation of your lilac tree. Check that the plant has well-drained soil and exposure to the afternoon sun (4 to 6 hours).

Check the existing plants located around the lilac tree. Crowding can affect the growth and blooming of the tree. Move any plants located at least 5 feet from the tree/bush and thin out around the lilac as necessary. Give the plant room to grow, and it will bloom beautifully every year.

Apply mulch in a light layer around the base of the lilac tree. Mulch retains moisture but also spreads water evenly throughout the ground. Lilacs will not thrive in soggy, damp soil due to root saturation.

Stir up the ground around the lilac tree every few years, and work compost or humus into the topsoil. Lilacs thrive in soil high in organic material. A 15-minute turnover of the soil and mixing in organic material assists the plant throughout the year, even during dormant periods.

Evaluate the pruning needs of your lilac tree. Pruning involves removing dead branches and long stems to control the shape and growth of the plant. Choose branches that warp the shape of the bush, and vary your choices to retain plant shape.

Clip close to the parent trunk of the lilac at a 45-degree angle. Use pruning clippers for branches smaller than 1/2 to 3/8 inch in size. Loppers work for branches up to 2 inches in diameter. Make clean cuts all the way through the branch. Don't pull or twist to remove clipped branches.

Look for signs of disease and infestation. Lilacs tend to be hardy and resistant, but some borer insects and mildews thrive on these plants. Powdery mildew (looks like white dust) can form on leaves. Treat the plant with a fungicide during the growing season. In the fall, collect all debris from the lilac in the garden and dispose of it. Pests can be treated with general pesticides to prevent damage to the plant.


Things You Will Need

  • Pruning shears
  • Pruning loppers
  • Humus or compost
  • Mulch


  • Lilacs don't require fertilizer to thrive under the correct conditions. If you choose to fertilize, select a type specifically designed for lilacs that doesn't contain too much nitrogen.
  • If your lilac needs a fresh start or has been damaged by pests, clip the plant down to the base stem of the plant. This type of rejuvenation pruning stimulates brand new, healthy growth for the entire plant. Lilacs won't bloom the year of rejuvenation pruning and will have slow bloom until the plant matures again.