Lilac bushes won't bloom

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I have had my lilac bushes for over seven years and they still will not bloom. What do I need to do for them?
  6 answers
  • Rita Lucas Rita Lucas on May 04, 2014
    You didn't say if the lilacs were getting any buds so I'll assume they don't. Start by lightly pruning out straggler branches. Come fall, prune back heavily to with in 36-48" off the base of the trunk. Come next spring they should flourish! Good luck
    • See 1 previous
    • Julie Sarrett Julie Sarrett on May 05, 2014
      @Rita Lucas - curious why the double pruning? I have a couple bushes and they are lush and green and growing almost too much for the space I have them planted. They are blossoming, but not a overload of blossoms, but are less than 5 years old. Wondering if the pruning would benefit the blooms?
  • Lilacs need full sun. This is usually why many do not bloom. You prune lilacs after they bloom in spring. You did not say if the foliage is lush and full. Fish fertilizer may be a good idea too. In poor soil and under Oaks they tend not to bloom as I have one i rescued a couple years ago.
    • See 2 previous
    • Sharlote Sharlote on May 05, 2014
      @The Garden Frog with C Renee MY Grandmother had it and it bloomed every year. I got a few roots from it. I think it is a 7 year but it has been 8 years. I live in Tennessee. I guess it needs fertilizer. thank you.
  • Douglas Hunt Douglas Hunt on May 05, 2014
    The Garden Frog's advice is spot-on. All early flowering shrubs should be pruned immediately after flowering or you risk losing next year's blooms. Make sure that any fertilizer you use is not too high in nitrogen.
  • Rita Lucas Rita Lucas on May 05, 2014
    Hi Julie, I normally don't double prune , however in Ruths case lightly pruning her Lilacs will "tell" the plant to bud. It nay give get a few blooms thus spring to enjoy. Pruning heavy in fall when the plant goes dormant "tells" the plant to reserve it's energy for next spring. Come next spring the plant should give her many lilacs to enjoy. And in your situation yes pruning will definitely help hut you'll need to wait until all the flowers are done for this season, otherwise you could send the plants into shock and it can harm instead if help. Come fall you'll prune yours back heavily as well once the plant is dormant. Cone spring you should also see many many blooms!
  • All day I have been thinking about your lilacs and decided when I was finished with a project to look up in my 70 year old gardening book about lilacs and what can be done. I did not want to give advice until I looked it up so here it goes: Lilacs usually do not bloom if there are too many suckers or branches coming off of the base of the plant so you if this is the case then you need to prune out the suckers and thin out the lilacs. #2 root prune the lilacs by taking a sharp shovel and making a trench all the way around the plant about 2' out. remove some of the soil and mix it with gernerous amonts of superphosphates (the book says about 8 oz to every 3 ft of ditch). #3 apply lime if the soil is acidic. You should also know that lilacs bloom profusely every other year. If you heavily prune the lilac now you most likely will not get blooms next year for sure and maybe even the year after. You can cut the dead branches, suckers, out and even old wood out to thin out the plants to allow more air flow and light to reach the new growth. Since these are your mother's lilacs, I do not know if they would have been grafted lilacs-which in this case may not be the original lilac and may not be a lilac. either way you need to prune out the suckers and thin out the lilac if it is tight knit and full. Hope this helps!
  • Michelle Leslie Michelle Leslie on Dec 17, 2020

    Hi Sharlote, you can prune or trim your lilac bushes to encourage new growth and blooms. Here's a great article and video that will show you how  https://www.thespruce.com/pruning-lilacs-how-and-when-to-prune-lilacs-1403004

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