Can I fertilize to help it bloom?

Too much nitrogen fertilizer can actually encourage leaf growth at the expense of flowers. Use a balanced fertilizer sparingly.

Do I need to deadhead the old flowers?

It is not strictly necessary, but removing spent blooms can help the plant focus its energy on next year's buds.

Lilac: not flowering, causes and fixes

Check these first

Count how many hours of direct sun the plant gets daily.
Check your pruning calendar to see when you last cut the branches.
Look for flower buds that may have been killed by a late spring frost.

Likely causes

Improper Pruning
Most likely
How to tell: You pruned the shrub in late summer or winter, removing the buds that were already set. Lilacs bloom on old wood from the previous year.
What to do: Only prune your lilac immediately after it finishes flowering in the spring. This gives the plant all summer to grow new wood for next year's blooms.
Insufficient Sunlight
Most likely
How to tell: The plant looks healthy and green but never produces flower buds. It is likely growing in a spot that gets less than six hours of direct sun.
What to do: Move the lilac to a sunnier location if possible. If moving is not an option, prune back nearby trees or shrubs that are casting too much shade.

Other plants that won't flower

Find out what's wrong with your lilac

The list above covers the usual causes. Pocket Botanist looks at a photo of your actual plant and tells you the likely cause, how serious it is, and what to try first. Identification and a health check are free.

When to worry

It is normal for very young lilacs to take 3 to 5 years before they bloom for the first time. Worry if a mature, established shrub has not bloomed for three years in a row.

Stopping it coming back

Always prune right after the flowers fade and ensure the plant gets at least six hours of full sun every day.

Lilac: not flowering? Check yours with a photo

Every plant is a little different. Take a photo of your lilac and Pocket Botanist tells you which cause is most likely, how serious it is, and what to try first. A few checks a day are free. Save the plant and you get care reminders timed for it.

Get the app · Or check it from a photo now, free

Questions people ask

Can I fertilize to help it bloom?: Too much nitrogen fertilizer can actually encourage leaf growth at the expense of flowers. Use a balanced fertilizer sparingly.
Do I need to deadhead the old flowers?: It is not strictly necessary, but removing spent blooms can help the plant focus its energy on next year's buds.

Why is my common lilac not producing any flowers?