Featured Expert
Nancy Rose
Research Horticulturist
Minnesota Landscape Arboretum
Chanhassen, MN

Q: I have a question about lilac bushes. Mine haven't bloomed for a few years. What do you think is wrong with them?

A: Probably the most common reason for a flowering shrub not to bloom is that it's in too much shade. Plants like lilacs and other flowering shrubs like mock orange, forsythia - these all need a lot of sunshine for them to bloom well. So these should be sited in your yard in a place where they get nearly full-day sun. They can take a little bit of shade, or perhaps part-day shade, but if they're in too much shade, the flower buds simply won't set. If your plant is in full sun, and it still isn't blooming, another reason why it might not be blooming is that it's getting too much nitrogen fertilizer. Perhaps you're fertilizing your lawn too heavily, and nitrogen is getting in to the shrub bed - too much nitrogen encourages leaf growth, but for the flower buds to set, they need less of the nitrogen and more of the phosphorus and potassium, the other important plant nutrients. So, check how much sun your plant is in, and then see if it's getting too much nitrogen.


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Last updated: Tuesday, February 01, 2005