Kids’ Valley Garden

Pruning Lilacs

Many old lilacs are pruned back to just a few old stems by cutting off all the new suckers. These lilacs will bloom only at the top and the flowers will get smaller each year. A well-pruned lilac will produce larger flowers with blooms from the top to the bottom of the shrub. If you have an old lilac bush that has gone unpruned for awhile it will take several years to return it back to its best. Make sure you have your parent’s approval before you start pruning an existing shrub. Ask for their assistance with the shears and a pruning saw.

Pruning a Lilac

  • The best time for pruning is right after the lilac has flowered usually in mid to late June.
  • First, remove any dead branches.
  • Count the number of main branches and select at least 1/3 of them to remove. This will open up the interior of the shrub and allow better airflow.
  • Look for branches that cross or rub against each other and remove one of them.
  • If you want to make your shrub easier to mow around, cut out any branches that are bent over or growing downward.
  • Check the suckers that are growing at the bottom of the bush. Cut off all but 3 or 5 of them.
  • If you want to keep your lilac bush shorter and have larger flowers remove any branch that is more than 3 years old but not more than 1/3 of bush at a time
  • If you kept some old suckers from last year, cut out to the same number of branches allowed to grow this year.

For example: Let’s say in 2007 there is a lilac bush with 6 old branches, 20 suckers that grew last year (2006) and 40 new suckers that sprang up this year.

  • Cut out 2 of the oldest branches leaving 4 old branches. Remove 18 of last year’s suckers leaving just 2 suckers and remove 38 of the new suckers leaving only 2.
  • Now your lilac has 8 branches of different ages.
  • In 2008 you will remove 2 of oldest branches and leave on 2 of the newest suckers(2008) to replace them.
  • In 2009 your shrub will still have 8 branches: 2 of the oldest growth and 2 suckers from each year after your started pruning the shrub.
  • This way your shrub will have a few original branches and only a couple new ones each year until all the old ones are replaced by new growth.

growing lilacs lilac varieties more shrubs

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