Spring has been slow to get underway this year but there’s hope in the tender shoots and tiny leaves now emerging. The greening of the landscape is a welcome sight after months of barren vistas.
So why am I urging you to go out there with your pruners and clop something? Isn’t it kind of cruel to take sharp implements to our little plants when they and the season are still so young? Well, no. If you think pruning is the hard-hearted removal of living limbs, akin to amputation, you don’t understand the real value of this essential gardening skill.
Pruning is undertaken for many reasons: To remove dead, diseased, deformed or poorly structured branches; to keep plants in bounds; to admit light and air into the heart of woody shrubs; to clear away last season’s dead leaves, allowing new shoots to emerge; to boost bloom, and to stimulate plants to send up new, vigorous growth.
Pruning is not merely cutting away. It can spare a plant unnecessary work, as when you pinch off spent flowers that would otherwise divert a plant’s energy to the production of unwanted seeds. It can reinvigorate plants grown lax and crowded, with a crush of stems jockeying for position like cars at rush hour. Pruning can also direct new growth, so the plant in question extends itself in a desirable direction.
Pruning, in short, is good.
Right now, you shouldn’t head out to the garden without sharp pruners and soft gloves. Walk around the yard, and you’ll see any number of opportunities where judicious nipping is indicated.
Old dead foliage of perennials should be removed before new growth appears and makes this a delicate operation. Ornamental grasses can be cut down within a few inches of the ground, as can tall, grassy perennials like Siberian iris. A smart gardener would bundle and tie the thin blade-like leaves together so they can be removed neatly in a clump, rather than flying all over and requiring that other essential spring chore, raking.
Cut down the dead stems of chrysanthemums, coneflowers, coreopsis and other clumping perennials, taking care not to damage any new leaves that may be peeking out.
You should have cut back and removed old peony foliage last fall to prevent the overwintering of botrytis spores that can blast the buds, but better late than never. Trim back the mess of old leaves surrounding the crowns of your hardy geraniums, lady’s mantle and pinks — you don’t want to look at that dreary stuff when these plants get ready to bloom.
Sub-shrubs are those critters that have some woody structure but still die back nearly to the ground every winter. Cut Montauk daisies and perovskia back to a viable bud 6 to 10 inches from the ground. Whack the butterfly bushes to a stump about the same height — they can easily make 6 feet of new growth in a season, and your flowers will be at nose height rather than waving somewhere over your head.
There are some plants that need a little more patience with the pruner. Lavender won’t sprout from “old” wood, meaning the woody stems of previous seasons. There’s no alternative to trimming stem-by-stem, removing the thin shoots that bore flowers last season. Give your lavenders a haircut now and they’ll look like beauty queens when they bloom in June.
Roses demand your prompt attention. Cut these back to living wood (a clear white, not black or gray inside) just above an obviously live bud. Remove all those blackened canes, brown stem tips and any crossing branches before pruning to make the shrub shapely.
Don’t worry that you’re left with a shrub that looks like a mere shadow of its former self. I’ve cut roses to the ground in anticipation of shovel pruning them (i.e., removing them entirely) only to have them sprout vigorously to full size in no time — foiling my cranky little plan to replace them with something more charming.
There are a few instances where we must say, “Pruner, hold that cut!” Don’t have at your spring-blooming shrubs like forsythia, azalea, lilac, rhododendron, deutzia, spirea or early-blooming viburnum until after they have flowered or you will be cutting away this season’s blossoms.
A good rule of thumb is to observe June 15 as the dividing line between spring-flowering shrubs — pruned after they flower — and summer-bloomers, which can be lightly pruned in spring. Of course, for every rule an exception: Mophead hydrangeas, the pink or blue ones, produce flowers on last year’s growth, and so should be pruned in spring only to remove winter-killed branches.
Also spare the foliage of spring-blooming bulbs, like daffodils, tulips and hyacinths, which often elongates after the flowers are spent. The bulb needs a period of vegetative growth to recharge itself for next year’s flowers before it goes dormant in early summer. Don’t braid the leaves or make them into ponytails with rubber bands, either — this is something to do to hair, not bulb foliage.
The great thing about spring pruning is that you shortly leave your garden looking neater and trimmer. And it keeps you occupied out in the garden while you wait out the chill and look forward to the heart of the planting season.