10 Neat Things about Deadheading & Pruning
by Dorothy Dobbie
by Dorothy Dobbie

The Local Gardener magazines, Ontario Gardener, Manitoba Gardener and Alberta Gardener, are published by Pegasus Publications Inc.

Drawing on her 30 years' experience as a senior executive in the magazine publishing industry, Dorothy launched Manitoba Gardener in 1998, initially running the business out of her home. Two years later, Dorothy's daughter Shauna, living in Ontario, jumped into the fray with Ontario Gardener. And two years after that, they started Alberta Gardener. Visit us at and register for our "Ten Neat things" newsletter. Watch Shaw TV for garden tips and Listen to CJOB for the Gardener Sundays at 9:08

June 6, 2017

1. Off with their heads, their legs, their arms.

Pruning or deadheading is the act of cutting away twigs or branches of a plant to a) remove dead or diseased plant material; b) remove spent blooms and encourage new blooms; c) to improve the form or shape of a plant; d) to encourage growth in a different direction, and e) to prevent seeds from developing. The beauty of plants over people is that they have the ability to grow new limbs, branches and roots to replace those that are removed. Pruning some plants will make them bushier, stronger and eager to grow new flowers and or twigs.

2. Cut to the roots.

Roots are the same as branches or twigs in that they respond to pruning by growing new roots. Don't worry if your new bedding plant comes in a six-pack that has to be cut or ripped apart so you can plant the flowers individually. Smaller garden centres and some box stores often plant up seeds in this manner and sell them at very low prices. The individual plants may have become pretty entangled and have overgrown roots. Rip them apart to stimulate new growth and trim off any compacted root growth.

3. The better to choke you with, my dear.

If you buy a potted plant and notice that the roots have begun to wind themselves around the root ball, unwind them. Otherwise this can cause strangulation of the plant. Spread the untangled roots out in the new planter.

4. The bloom is off the rose - er, petunia.

Remove spent blossoms from annuals and to encourage continued flowering. Deadhead the whole flower head, including the calyx at the very base of the flower and the stem the blossom is growing on, right back to the nearest main stem or place where two new leaves are growing.

5. Are there any annuals that I shouldn't deadhead?

If you want to collect seeds, don't deadhead. You want the bloom to fulfill its full cycle and go to seed. Today, most of the hybrid petunias need little or no deadheading as they are bred to be "self-cleaning", meaning that their blossoms will drop off and be replaced by new ones. However, even these plants will benefit from a bit of pruning (cutting the stems back as much as two-thirds) about mid-season to keep them from getting leggy. Click the image on the left to view a list of annuals that need little to no deadheading.

6. Oh no, my peony died when I pruned it.

No it didn't. It just won't bloom again till next spring . Most perennials bloom only once a season so deadheading is just a matter of housecleaning to make the plants look tidy by removing spent flowers. Roses, dianthus, and catmint are a few of the exceptions. There are a few new perennials that are bred to keep on blooming through the season but they are mostly self-cleaning. Some perennials such as delphiniums can be encouraged to bloom a second time by pruning or cutting back the whole plant after the first bloom.

7. Can I prune shrub and tree roots?

If you are planting trees or shrubs, it is very likely that the roots have been pruned when potted or bagged. Just be sure before you plant, that the roots aren't wound around the root ball. Pull them away from the ball and spread them out.

8. Why should I prune my shrubs?

In general, trees and shrubs will not die if not top-pruned, but pruning can encourage new growth in a different direction. In some trees and shrubs, it can cause bushier growth. Cutting out disease can help the plant resist insect infestations. If pruning out disease, sterilize pruners in 10 per cent bleach between each cut. When it comes to evergreens, be cautious. The best rule of thumb for beginners is never to prune more than a third of the way back on any branch and to do this in June after the tree has put out new growth. There are some evergreen trees that can be pruned in early spring and again after the new growth has occurred.

9. I wanna trim those lilacs.

Woody plants require careful consideration before pruning. If the shrub produces flowers, you need to know if the blooms are produced on new wood or old to avoid losing a season's blooms. (Spring blooming plants mainly bloom on old or last year's wood, including most lilacs). Pruning shrubs means more than just giving the plant a haircut. Many shrubs benefit from thinning, which means cutting out heavy growth from the root up. Beginners should get more guidance before proceeding. Cutting out dead or diseased branches can be done at any time. Prune plants that bleed sap, such as maples and birches, after the leaves are out.

10. Where should I prune?

Look for the swelling, or the branch collar, at the base of a stem or branch where it meets the main stem. Prune just at the outside edge of the swelling (away from the trunk). This swelling, called the branch collar, is where the tree manufactures its healing tools. Proper pruning allows the tree to self-heal the wound without the aid of artificial tars or resins. Don't leave stubs. If pruning just a portion of a branch, prune back to the nearest node or the place where new growth would begin. Look for an out-facing node so as not to encourage growth toward the inner part of the tree which can cause branch crossing and reduce light at the core of the canopy

Dorothy Dobbie Copyright© Pegasus Publications Inc.

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