Deciduous plants store their energy in their roots during the winter. In the spring, this energy is used to develop foliage and new stems.
Therefore, if you prune your overgrown deciduous shrubs now, all of that energy will be put into new growth, resulting in a newly shaped plant that you can manage a lot easier.
When using the rejuvenation technique, you cut all of the stems and branches back to just above (3 to 4 inches) the base of the plant. The result is a smaller, more manageable plant that looks a lot better in the landscape.
Not every deciduous plant responds quickly to rejuvenative pruning, and it’s not a technique to use on evergreens such as taxus, juniper and arborvitae.
The plants that respond best to this type of pruning are forsythia, rose-of-Sharon, privet, honeysuckle, spiraea and lilac. Most viburnums will also tolerate this type of pruning, though some species may take longer to recover than others.
Don’t wait to rejuvenate a plant after it leafs out, as this sets the plant back a little. Most of the stored energy has been used.
However, some plants like forsythia and spiraea are such vigorous growers that this doesn’t seem to bother them too much.
Evergreens don’t respond quickly at all to rejuvenative pruning. They store their energy in their leaves; therefore, if you remove a significant portion of the plant, there is not a lot of energy reserve for new growth.
You can cut junipers, taxus and arborvitae quite a bit and they will survive, however, keep in mind that they don’t grow fast and it may take years to fill in.
Another technique is renewal pruning, or removing one-third of the old stems per year in order to allow the new growth to emerge.
This is a good technique to use on lilacs. Take out the older wood in the middle of the plant and you will see new branches come from the base of the plant.
Typically, when pruning flowering shrubs, you should prune after they finish blooming in order to prevent cutting off the flower buds. However, when using rejuvenative pruning, you have to sacrifice a year of blooms to get a better plant. It’s worth it in the long run.
Pam Corle-Bennett is an Ohio State University Extension
horticulture educator and the state Master Gardener volunteer coordinator.
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