Lilac Bush Not Blooming

By Ellen Brown

Q: I have a lilac bush that has never bloomed. I have had it for 10 years, it gets green leaves and that is all. I have cut it back as I was told to do, but I still don't get any blooms. Please reply with anything you think may help.

I am in zone 6

Thank-you,
JMS

A: JMS,

You can try using the process of elimination. There are five main reasons that lilacs fail to bloom: insufficient sunlight, too much nitrogen fertilizer, improper planting (planted too deeply), improper pruning (pruning at the wrong time) or winterkill of the flower buds. If you are fertilizing your bushes (or near your bushes), stop. Lilacs set their flower buds for next year on this year's growth. If you pruned them last season in late summer, say late July or August, you may have removed the flower buds for this growing season. Also, lilacs will typically not bloom the season after a harsh pruning, so you may need to wait until next year before you see flowers. If you suspect winter damage to your flower buds, you can only hope for milder winters or plant a hardier variety. Pulling some soil back from the roots will help if you think it may be planted too deeply. Lilacs need full sun to flower. You might take a sucker from your lilac bush and try growing it in a new location.

Ellen

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Q: I have lilac bush a friend gave me. I planted it 9 years ago and it has never bloomed. Please help. I don't know what to do.

Hardiness Zone: 5b
Cheryl Hubbard from MO

A: Cheryl,

There are several reasons lilacs don't bloom. The most common problem is a lack of sunlight. In order to bloom, lilac bushes need at least 6 hours of sun per day. If your lawn (or your neighbor's lawn near your lilacs) is frequently fertilized, your lilacs may also be getting too much nitrogen. Nitrogen promotes lush foliage, while inhibiting flowering. When planted in decent soil, lilacs usually do just fine without fertilizing. If they need it, use a fertilizer with a high ratio of nitrogen (second number) and apply it in the early spring. Organic sources include bone meal and fish emulsion. Incorrect pruning is another common problem.

Pruning should be done no later than mid summer (July) or you risk cutting off next years flowers. You may have also planted your lilacs too deeply. If you think this might be the case, pull back some of the soil so the tops of the roots are slightly exposed. Also, you don't mention what type of lilacs you're growing. Common lilacs need cold winters in order to set their flower buds, but these same cold winters can kill the buds of less hardy varieties. Finally, lilacs prefer slightly alkaline soil (pH 6 to 7). Having your soil tested is the only way to know whether or not it's too acidic.

Hope this helps.

Ellen

About The Author: Ellen Brown is our Green Living and Gardening Expert. Ellen Brown is an environmental writer and photographer and the owner of Sustainable Media, an environmental media company that specializes in helping businesses and organizations promote eco-friendly products and services.

Answers:

Lilac Bush Not Blooming

I have the same problem with my lilac bush. My grandmother told me that it will not bloom unless there is another lilac bush near. I am not sure how "near" it needs to be. I have checked out other blooming lilac bushes and there's always another bush near by. I am not sure how true this is, but Grandmother has been around for 83 years and she can grow anything. (05/01/2006)

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