Wednesday, September 11, 2019

Fall Division

Hooray! Garden Club is waking up from its summer nap and will be opening its doors again on September 24th. A timely reminder from Gwen regarding Fall division of perennials prompted me  to "root" around for some helpful information.


After a few years in the garden,  perennials may start to produce smaller blooms, develop a 'bald spot' at the center of their crown, or require staking to prevent their stems from falling over. All of these are signs that it is time to divide.


Why divide perennials?

To rejuvenate the plant and stimulate new growth

Overcrowded plants compete for nutrients and water.
Restricted airflow can lead to diseases.
Dividing the plants into smaller sections reduces this competition and stimulates new growth as well as more vigorous blooming.

To control the size of the plant

Since plants grow at varying rates, division may be used to keep plants that spread rapidly under control.

Guidelines for dividing perennials

Divide perennials on a cloudy, overcast day as dividing on a hot sunny day can cause the plants to dry out.
Water the soil a day in advance if the area to be worked on is dry. Ideally, divide plants when there are a couple days of showers in the forecast to provide enough moisture for the new transplants.

How to divide perennials

Dig up the parent plant using a spade or fork.

Gently lift the plant out of the ground and remove any loose dirt around the roots.

Separate the plant into smaller divisions by any of these methods:

Gently pull or tease the roots apart with your hands;

Cut them with a sharp knife or spade;

Or put two forks in the center of the clump, back to back, and pull the forks apart.

Each division should have three to five vigorous shoots and a healthy supply of roots.

Keep these divisions shaded and moist until they are replanted.

Replanting

For clump-forming perennials, choose the strongest parts from the outside of the plant and replant a few pieces to replace the original plant. The extra pieces can be planted in new areas or potted up to give away. Keep newly-potted plants in the shade – they are already stressed enough.

When replanting the newly divided perennial, add compost or well-rotted manure to enrich the excavated soil. Plant the divisions at same level they had been growing at in the newly prepared hole. Tamp the soil firmly around the plant. Water immediately and keep watered for the next few weeks to help it survive the shock. Discard or compost the woody centre of the old plant.

When to divide

Divide when the plant is not flowering so it can focus all of its energy on regenerating root and leaf tissue.

Divide fall blooming perennials in the spring because

New growth is emerging and it is easier to see what you are doing.
Smaller leaves and shoots will not suffer as much damage as full-grown leaves and stems.
Plants have stored up energy in their roots that will aid in their recovery.
Rain showers that generally come along with the early season are helpful.
Plants divided in spring have the entire growing season to recover before winter.
Spring dividing should be done when a couple of inches of growth are showing.

Divide spring and summer blooming perennials in the fall because

There is less gardening work to do in the fall compared with spring.
It is easy to locate the plants that need dividing.
Perennials with fleshy roots such as peonies (Paeonia spp.), Oriental poppy (Papaver orientale) and Siberian iris (Iris siberica) are best divided in the fall. The perennials that have begun to show signs of going dormant with browning foliage can also be moved or divided in early fall.
When dividing plants in the fall, time it for four to six weeks before the ground freezes for the plants roots to become established.

For a list of specific plants click on the topic at the top of the page beneath the title picture.

Information courtesy of University of Minnesota Extension and Toronto Master Gardeners

2 comments:

  1. A timely reminder. Thanks Sue!

    Joyce R.

    ReplyDelete
  2. good info and a reminder to me to pot up plants that become "extras"--for another area or for the spring plant sale.

    ReplyDelete

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