How to Properly Trim Shrubs

When should I trim shrubs?

Trimming shrubs and small trees in the landscape is an important practice. It helps ensure your ornamentals appear the way you would like for them to. It is important to remember that different plants should be trimmed or pruned at different times and the proper pruning method varies by plant.

When should I trim my shrubs?

Either before or after they flower depending on the variety.

How do I trim my shrubs?

There are three main methods: heading back, thinning or renewal pruning

Trim before or after the shrub flowers?

As a homeowner, it is important you trim the shrubs at the proper time. Some shrubs should be trimmed before they flower and others should be pruned after.

Trim these shrubs before they flower:

  • Camellia
  • Crape myrtle
  • Gardenia
  • Nandina

Trim these shrubs after they flower:

  • Azalea
  • Hydrangea
  • Climbing roses
  • Dogwood
  • Forsythia
  • Indian Hawthorn
  • Weigela

Shrub trimming methods

There are three main types of shrub trimming or pruning. These are heading back, thinning or renewal pruning. The method you use depends on your desired look for the shrub and the plant variety.

Heading Back

The heading back method creates dense outer foliage. This method works well for shrubs that are designed to be hedges, such as holly varieties.The below photo shows the proper method for heading back. Click here for the original post.

heading back shrubs proper cut

Thinning

Thinning is a good method for trimming shrubs that does not cause excessive growth. This is a great method for crape myrtles, viburnum, and boxwoods. The below photo also comes from the link above.

shrub thinning prunning

Renewal Pruning

Renewal pruning is used when the shrub or tree has outgrown its desired size or appearance. Not all shrub or tree varieties can be pruned in this manner. To perform a renewal pruning, the plant should be cut to within 6 to 12 inches off the ground. This pruning should occur in late winter before spring growth occurs. Use caution to ensure the pruning is done after the last frost. This eliminates the possibility that new growth could experience cold damage. It is best to perform this type of pruning in stages over time. Read what Clemson has to say about renewal pruning.

Crape Myrtle Pruning

Many homeowners and some inexperienced landscapers mistakenly over-prune crape myrtles using a method called topping. This leads to an eyesore and is hard to recover from. The below photo from Clemson highlights the problem caused by this pruning method.

incorrect crape myrtle pruning

To avoid this look on a crape myrtle, prune the small twigs, remove lateral branches, remove any branches that are crossing or rubbing other branches, and continue to remove any undesirable shoots.

Sever pruning does not increase flowering and instead could lead to a less than desirable appearance for crape myrtles. Use the below photo from Clemson as a guide.

proper crape myrtle pruning

Help with shrub pruning

If you do not feel confident in pruning your own shrubs, contact a professional.

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