Tips for Pruning Perennials

May 26, 2017

Did you know that you can prune your perennials to help delay or prolong the blooming period on them? A technique called preemptive pruning will help you achieve this effect.

Delaying the flowering of your perennials with preemptive pruning can be useful if you have a party or event coming up that you want your perennials out in full flowering force but it’s beyond the normal flowering time for your perennials. Preemptive pruning can be done by either pinching or shearing your perennials back.

Before we delve into the different preemptive pruning techniques, here are some reasons why you may want to prune your perennials:

  • Extending the blooming period
  • Encouraging new growth
  • Staggering plant height and/or bloom time
  • Reducing plant height
  • Keeping plants in their own space
  • Cleaning up your garden
  • Controlling pests/diseases

Variables that effect pruning perennials include:

  • Regional differences
  • Annual weather conditions
  • Soil conditions
  • Age and vigor of the plant

And tools you’ll want ready to go before you start pruning your perennials:

  • Head shears
  • Bonsai shears (for deadheading)
  • Felco shears
  • Hori hori

The Pinching Technique

If you’re a little hesitant, you can start with pinching. This method is good for beginning gardeners. Not only will it help delay flowering by a few weeks, but it can also help with the structure of your plants by keeping them more compact.

Pinching is best done early in the season that your plant typically blooms in. It is good to know that if you pinch your perennials in autumn, it will delay the flowering too much so they won’t bloom anymore during that season.

Pinching can be done by removing the top couple inches of new growth with either a sharp pair of shears or with your thumb and index finger.

Pinching Perennials Photo Courtesy of Gardening Know How

Pinching Perennials Photo Courtesy of Gardening Know How

Do not pinch or shear perennials that only have one single flower stem as this will remove its only bud so instead of encouraging more blooms, you will just remove the flower all together.

Some of these single flower stem plants include:

  • Astilbe
  • Hosta
  • Papaver (Poppy)
  • Heuchera (Coral Bells)

If you want to stagger the blooming on your perennials, instead of pinching all the tips, you can selectively pinch half of the plant so that way you have some buds blooming at the normal time and then you’ll get another round of flowers a couple weeks later.

Some perennials that respond well to pinching are:

  • Heleniums
  • Chrysanthemums
  • Phlox
  • Asters

The Shearing Technique

If you’re a more experienced gardener/pruner, you can also preemptively prune by shearing back up to half of the plant. Not only will this delay flowering and help structure your perennials, but it can also help with flopping issues.

Shearing Perennials Photo Courtesy of My 1929 Charmer On the left shows how not to shear and the right is the correct way to shear your perennials.

Shearing Perennials Photo Courtesy of My 1929 Charmer. On the left shows how not to shear and the right is the correct way to shear your perennials.

You can also prolong the blooming period of some seeding plants by cutting them back before they seed to get a more perennial type plant.

Tracy DiSabato-Aust has a great book called The Well-Tended Perennial Garden that goes more in depth about preemptive pruning and which plants do and do not benefit from this pruning technique.

You can also view a list of plants, provided by Tracy, that benefit from preemptive pruning here. At that same link, you will also find lists of perennials that benefit from other types of maintenance such as deadheading, deadleafing, and disbudding.

Deadheading Photo Courtesy of Royal Horticultural Society

Deadheading Photo Courtesy of Royal Horticultural Society

Do you want an easy to maintain landscape that includes beautiful perennials? Contact us today to see how a landscape design can help you transform your outdoor space!

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