I have spoken with many of you about rejuvenation pruning recently so I thought I should write an article about it and share this underused practice with more people. If you are like me and moved into a home where the landscape had not been maintained in ~10 years, and well-established plantings bore a strong resemblance to Cousin Itt, then rejuvenation pruning could be your ticket. Rejuvenation pruning is the practice of drastically pruning a shrub to within 6-12” of the ground so as to jump-start its energy into new growth.
BRAVERY: Rejuvenation pruning may seem scary and excessively harsh, but knowledge of these two things can help you move forward: - Perennial shrubs store their energy in their roots so it is all but impossible to kill them by cutting what is above ground - New growth and flowers grow on last years’ wood. This means that if un-pruned, the shrub will get larger and larger every year with the growth only occurring on the outer foot or two; resulting in a dead-looking and leafless interior
TIMING: Rejuvenation pruning can realistically happen any time of the year, but if you prune outside of optimal times you can cheat yourself out of a season of bloom. Prune spring blooming shrubs such as Lilac, Prunus, Forsythis, Mockorange, Amelanchier, Cotoneaster and certain varieties of Spirea as soon as the flowers are done in the late Spring and before much new growth has started. If this pruning is done in the fall or winter you will remove the flower buds that have set for next years’ growth. Summer blooming shrubs such as Coralberry, Oregongrape Holly, Potentilla, Roses, St. Johnswort and Sumac should be pruned in the late winter or early spring before new growth begins. Pruning after growth has started will remove buds for this year’s blooms.
STAGED PRUNING: If cutting back the entire shrub feels too drastic, or doing so would have a negative impact on the visual appeal of your landscape, consider gradual rejuvenation pruning. The same thing can be accomplished over the course of a couple of years, but you will remove all of the branches in stages as opposed to all at once. This method takes longer to accomplish but the shrubs remain more attractive during the rejuvenation process.
Now get out there and hack your shrubs down to the ground! They will be better for it.