North Shore Gardening Life

Days Until First Frost

My Lilac Flowers Have Finished Blooming. What do I do?

Patricia asks what to do now that her lilac flowers are finished.

Elizabeth’s Reply:

The answer is DEADHEAD, which, as the word suggests, means cutting off the dead flowers.

But only if you want to.  There is a story that deadheading lilacs will produce more flowers the following year.  In my experience lilacs seem alternate good years and bad years regardless of whether you deadhead or not.  It does tidy things up though.

How do you deadhead?  Take the dead  flower in your hand and slide back to the nearest set of buds or leaves on the stem and cut diagonally just above that.

The main thing to remember about lilacs is that they bloom on the previous years’ growth.  So if you prune them later this year after a lot of new growth, you are basically cutting off next year’s flowers.

That’s why if you want to shape the bush or get rid of some unruly branches, you should prune back as soon as you can after the flowers have faded.  In other words, NOW.

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3 Responses

  1. Janine Jaconelli wrote:

    Hi Elizabeth and Jennifer- Love your Blog.

    We are having issues with our lilac bush. It is located at the front of our home, we keep it trimmed and it has healthy leaf growth, however, has not flowered in 4 years. Any thoughts on what we can do for next spring would be appreciated. (missing the fragrant smell of spring)

    Hi Janine

    If you saw our article on what to do when when lilacs have finished blooming, you will know that deadheading the flowers is important. However, since you don’t have any flowers, that’s not particularly useful advice, is it?

    There are a couple of factors that might be at play here. It sounds as if the lilac has bloomed before, so my first question would be: is it still getting enough light? Have surrounding trees started to shade it out? Lilacs need at least 6 hours of sun a day to succeed.

    Sometimes the branches get crowded and not enough sun gets into the bush, so judicious pruning might be in order to open it up a bit.

    Second, although lilacs don’t need that much fertilizer, if they get too much nitrogen they will probably have beautiful leaves but hardy any flowers. You can use Miracle Gro for shrubs in the early spring as the leaves are just coming out (but not now), or, you can scratch in some bone meal and mulch with composted animal manure now.

    Third, as I mentioned in the article, make sure you do your pruning NOW, don’t leave it any later, or you will be cutting off next years’ flowering buds.

    Hope this helps.


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