Lilac Bush Not Blooming? Here’s What to Do

It can be frustrating if a lilac bush is not blooming. Get expert advice to fix this problem. Plus find out if lilacs need full sun or prefer shade.

Why Is My Lilac Bush Not Blooming?

Shutterstock 194180936Shutterstock / Iryna1
Blossoming lilac flowers

“I was given a small lilac bush years ago from a friend’s garden. Every spring I’m so disappointed to see no flowers. How can I get it to bloom?” asks Birds & Blooms reader Georgette Jahn of Dingmans Ferry, Pennsylvania.

Horticultural expert Melinda Myers: Shade and improper pruning can prevent lilacs from flowering. Make sure your plant receives at least six hours of sunlight. If not, consider moving it to a sunnier location. Avoid high nitrogen fertilizer because it can prevent flowering. Only prune lilacs right after their normal bloom period in early summer if you want flowers the following spring. Pruning at other times eliminates the flower buds and your spring bloom.

Why We Love Lilacs: So long-lived that it often survives even after a house is long gone, a lilac bush needs no coddling beyond regular watering its first year.

If you live in the Deep South, try growing lilac vine.

Do Lilacs Need Full Sun?

“When and where should I plant lilac bushes? Do they need full sun?” asks reader Elizabeth Williams of Portland, Oregon.

Melinda: Lilacs flower best in full sun with at least six hours of direct sunlight a day. Plant your lilac in an area with moist, well-draining soil. They prefer neutral to slightly alkaline soil. Portland soils tend to be somewhat acidic, so it’s best to have your soil tested before adding lime to adjust the soil pH to make it neutral to slightly alkaline.

Does a hydrangea need full sun or shade to grow best?

Do Lilacs Like Acidic Soil?

Bloomerang Purple Syringa 8801 lilac bush not bloomingVia Proven Winners
Bloomerang Purple reblooming lilac bush

“My lilac bushes have never bloomed. They get some direct sun, but some shade. The soil is acidic because of pine and oak trees. Is this the problem?” asks reader Joanne Eastman of Lovell, Maine.

Melinda Myers: Evergreen needles and oak leaves have little to no impact on soil acidity. Plus, acidic soil would cause leaf discoloration and stunted growth, not merely a lack of flowers.

The shade from these trees may be the culprit. Lilacs flower best with at least six hours of direct sunlight. Too much high-nitrogen fertilizer and improper pruning can also result in a lack of flowers. Go easy on the fertilizing, and prune only if needed right after the lilacs should have bloomed. These plants develop their flower buds in the summer, and the buds then open the following spring.

Backyard Tip: Do you really love lilacs, but wish they bloomed longer? Check out the new reblooming lilac options out there, like Bloomerang Purple from Proven Winners. New Age White Lilac is another fresh update on the classic shrub.

Sources:

Melinda Myers

Proven Winners

Lori Vanover
Lori has 20 years of experience writing and editing home, garden, birding and lifestyle content for several publishers. As Birds & Blooms senior digital editor, she leads a team of writers and editors sharing birding tips and expert gardening advice. Since joining Trusted Media Brands 13 years ago, she has held roles in digital and print, editing magazines and books, curating special interest publications, managing social media accounts, creating digital content and newsletters, and working with the Field Editors—Birds & Blooms network of more than 50 backyard birders. Passionate about animals and nature, Lori has a Bachelor of Science degree in Agricultural and Environmental Communications from the University of Illinois. In 2023, she became certified as a Wisconsin Extension Master Gardener, and she is a member of the Wisconsin Society for Ornithology and sits on the organization's Publications Advisory Committee. She frequently checks on her bird feeders while working from home and tests new varieties of perennials, herbs and vegetable plants in her ever-growing backyard gardens.