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The Spokesman-Review Newspaper
Spokane, Washington  Est. May 19, 1883

Plantamnesty Offers Help For Spirea Pruning

Phyllis Stephens Staff writer

While plowing through old garden journals, I came across an informative article describing proper methods for pruning spirea. The article was written by Cass Turnbull, executive director of PlantAmnesty. PlantAmnesty is an organization based in Seattle dedicated to ending mispruning and improper landscape management practices.

For most of us, spirea conjures up thoughts of huge, unruly bushes associated with old, established gardens. In the spring, they’re usually covered with white flowers and bees. It’s the unruliness that gives these specimens their bad reputation. Often they look like a five-foot pile of brown twigs frosted with a handful of small green leaves. When dealing with this pile, one’s first inclination is to bring it down to a more acceptable size, to make it smaller. It’s here the real trouble begins. This desire to make large plants small usually results in shearing, a pruning method that should be reserved for bonsai or formal hedges.

According to Turnbull, we should prune plants to make them better, not shorter. When we prune to make a plant smaller, it’s amazing how quickly it grows again, trying to regain its original height. Also by shearing the spirea into a perfect square or lobe, we destroy its graceful, arching appearance. Usually we’re left with a round ball of brown twigs, a few leaves and fewer flowers. Yet this common mistake of shearing is done over and over again on these beautiful plants.

Shearing simply increases the growth rate, making the plant thick with branches, barren stems and few flowers. Every place a cut is made, three or more shoots emerge from the cut end.

Although shearing is fast, and a real no-brainer, it is self-defeating, according to Turnbull. “The newly stimulated regrowth quickly destroys the neat and tidy sheared look. And therefore, in the not-so-long run, it is more expensive than selective pruning. The more you shear, the more shoots you get, which need to be re-sheared, leading to a greater number of shoots, and on, and on. One is locked into a constant battle, and the plants look like heck half the time anyway,” she says.

The proper method for pruning spirea is selective maintenance pruning. Properly pruned shrubs look natural when they’re trimmed correctly, sort of like a good haircut. Pruning for the plant’s health and natural beauty means low maintenance, because we prune less frequently.

Make the cuts on the spirea deep inside the shrub, not out at the perimeter. Search the shrub for the longest, most unruly branch. Grab it with one hand and follow it to some place well inside, hopefully where it joins a side branch or to a bud. Don’t become too tied up searching for buds. There are dormant buds just about everywhere on the stems of this plant. Wherever you make the cut, a new branch is sure to develop.

Once these long fellows are dealt with, stand back and survey your work. Then do some tidying up if necessary, always keeping in mind maintaining the plant’s natural appearance. If done correctly, you’ll have a lovely, graceful specimen in your garden.

If your spirea looks terrible, and you’ve tried selective pruning to no avail, then perhaps radical renovation is in order. This simply means cutting the spirea to the ground. This doesn’t mean you’re killing the plant. The hardy, mature root system will sprout new growth in no time. However, this new growth will be straight, lacking the graceful arching of older limbs. When the shrub reaches its desired height, the branches will begin to arch, thickenup and set more flower buds.

, DataTimes MEMO: If you would like to know more about PlantAmnesty and the availability of the group’s free pruning guides, call (206) 783-9813 or write PlantAmnesty Headquarters, 906 NW 87th St., Seattle, WA 98117.

If you would like to know more about PlantAmnesty and the availability of the group’s free pruning guides, call (206) 783-9813 or write PlantAmnesty Headquarters, 906 NW 87th St., Seattle, WA 98117.