When is the best time to prune plants?

Brian Jervis Ask a Master Gardener

“I kind of let some of my shrubs overgrow this year. Is this the right time to prune these shrubs? —SH

With the heat we experienced last summer, it was easy for many of us to let our landscape get a bit ahead of itself, but now is not the best time to prune. Before we explain why, let’s talk about why we would prune our plants in the first place.

In the Midtown Tulsa neighborhood of Avalon Place, you’ll find this week’s showcase home: 3031 S. Trenton Ave. Photos courtesy of Trevor White

One of the reasons we prune our plants is to stay on top of the plant’s shape. As a general rule, it is best to remove less than a third of a particular plant when pruning. We do this so that the tree does not go into shock and has enough resources to feed itself. If we lack pruning over a period of years, it’s easy for plants to become deformed or grow in certain areas that could cause a problem, such as rubbing against the house or roof. Just accept that to get this plant back to where it should be, it may take several seasons to only remove up to a third of the plant at a time.

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Pruning can also be used to train your plant. If you want your plant to grow more in a vertical direction rather than a horizontal one, keep those horizontal branches trimmed so that the plant devotes more energy to its vertical growth.

Pruning can also help keep your plants healthy. We keep them healthy by removing overcrowded branches or perhaps branches that are rubbing against each other. Rubbing branches will rub the outer layer of bark, making the plant more susceptible to disease. It’s also a good idea to prune dead or dying branches.

Trimming can be done any time of the year without killing your plants, but there are times when it’s best. Try to remember to prune at the best time for the plant, not the best time for the pruner.

In general, a good time to prune most plants is in late winter or early spring before new growth begins. Spring pruning just after new growth begins is not recommended. Late summer is also not a good time because pruning at this time can encourage new growth, and this new growth is more susceptible to damage from a cold winter.

Overall, the best advice on pruning is to know your plant and its needs. For example, take hydrangeas. The bigleaf hydrangeas that most of us are familiar with look rather scruffy in winter with their bare brown branches. Many gardeners cut these stems to the ground in the winter to create a neater garden, then they are confused when they get no flowers the following spring. The reason for this is that the flower buds for next year’s flowers are already set on these stems. Removing the stems makes your garden a little neater, but it also means there won’t be any flowers next year.

We have a long list of when to prune a wide variety of plants on our website in the Hot Topics section. Just look for where it says “Pruning Schedule”. Good luck.

You can get all your gardening questions answered by calling the Tulsa Master Gardeners Helpline at 918-746-3701, visiting our Diagnostic Center at 4116 E. 15th St., or sending us a email to [email protected]

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