Prune Your Bloomers Now!

What an amazing display of lilacs we had this spring! Beautiful purples of every hue colored the entire town. Perhaps the reason for this was the late freeze last year that killed most lilac flower buds leaving us with a very meager floral display. Perhaps the conditions for abundant blossoms aligned perfectly. Who knows?

A gardener can encourage prolific blooming next spring, with proper pruning and care this year. When a flowering shrub, such as lilac, forsythia, mock orange, quince, beautybush or viburnum, finishes blooming, it’s time to prune it. Next year’s flowers develop on this spring’s wood. If you want a good display of flowers next year, prune your bloomers now. Pruning in the fall cuts the flower buds off, destroying any potential blooms next year. If you don’t prune your plants, you can end up with a tall woody plant with very few flowers. Ideally, you want a mixture of older stems and younger growth.

To prune a shrub properly, here are a few tips:

  • Systematically remove the large old branches greater than two inches in diameter with heading back and thinning cuts.
  • Do not remove more than one-third of the branches in a single year.
  • Keep a mix of pencil thin stems up to stems 1 to 2 inches in diameter.
  • Shape the bush as you are pruning.

Heading back is selectively cutting terminal shoots and branches back to a lateral bud. This stimulates vigorous new shoots and denser foliage. Cut the branch back to ¼ inch above a bud facing the direction you want the new shoot to grow.

Thinning is the removal of an entire stem. Use this for cutting out deadwood or large old branches. You can shape by thinning also.

However, if you are trying to get a large older bush that is out of control back into shape, you may want to simply cut the entire bush back to 10 to 12 inches from the ground. New growth will sprout from the stumps. Next spring you will have to prune out the weaker stems and shape the bush keeping the better growth. It won’t bloom for several years after this drastic pruning.

To remain at their best, lilacs need a bit of maintenance pruning each spring. At the very least, cut off the spent blooms. For more information call 887-2252 or email skellyj@unce.unr.edu.