Q: All of a sudden it’s March and I realize I should probably be pruning something. What, in fact, should I be pruning? — J. C., Hatfield
A: Your instincts are correct, J.C. There is something so satisfying about knowing we have a predictable gardening routine based on Mother Nature’s consistent spring awakening schedule.
Before you take those freshly cleaned, oiled pruners and get them busy, though, take pause. Do your shrubs and trees really need pruning? They already have a natural form and often look best when left alone. That said, there are situations when pruning in late winter/early spring is helpful to the plant. It is also the time when pruning cuts heal the fastest.
One such pruning situation is taming an overgrown deciduous shrub. By now its leaves will have fallen off leaving clear visibility of the branches, which gardeners call the “bones” of the shrub or tree, making it easier to see which ones need pruning. Overgrown shrubs and trees benefit from pruning out ⅓ of the oldest stems as this introduces fresh airflow among remaining stems and encourages new growth. Pruning more than ⅓ per year puts excessive stress on the remaining leaves and roots.
Another beneficial type of early spring pruning focuses on the plant’s health. Do you see places where limbs are rubbing against each other? Trim the one that is least consistent with the overall appearance and growth habit of the plant. Is there a dead branch? Pruning it down to either the base of the branch or the first healthy crotch will stimulate new growth. Too many young branches in the base? Trim away excessive branches in an orderly pattern so what remains appears balanced. Again, stick with the “prune no more than ⅓” rule.
Contrarily, think before pruning spring flowering shrubs such as forsythia, lilac, magnolia, azalea, mountain laurel and ornamental fruit trees. Pruning them now will remove flower buds and give you less of a show. If you do not mind losing a few blossoms, go ahead and prune them. If you do, wait to prune until just after the blooms are spent. It is always good to research what works best for your particular plant species and specific variety.
Also, avoid pruning trees whose sap runs heavy in the spring such as maples, birch, walnut and elm. Pruning them may cause them to lose excessive moisture. Better to prune them mid-summer.
Refrain, too, from the urge to prune winter burn, where the leaves have turned brown and shriveled, as later this spring the tips or areas further down the branch may re-sprout. Broadleaf evergreens such as rhododendrons, azaleas, mountain laurel and holly are especially susceptible to this type of damage.
A couple terrific upcoming workshops to help you learn how to prune your shrubs and trees as a home gardener are the “Super Cuts” workshop offered by Dan Ziomek of Hadley Garden Center and the “Healthy Trees and Shrubs” workshop offered by arborist Ken Gooch at the Saturday, March 30 Western Massachusetts Master Gardener’s gardening symposium at Holyoke High School in Holyoke, MA. Visit wmmga.org for details.
Enjoy getting out in the gradually warmer weather — spring is almost here! Thanks for asking a (local) Master Gardener.
Have a gardening dilemma? Please send questions, along with your name/initials and community, to the Western Massachusetts Master Gardener Association at AskAMasterGardener@wmmga.org. One question will be selected and answered per week. wmmga.org