Puslinch Pioneer—March , 2020
By Margaret Stewart, Guelph and Wellington Master Gardeners
Question: In spring, what are some ways to prepare perennial beds/mixed borders for the coming season?
When the snow melts, winter-crazed gardeners eagerly anticipate spring clean up. If we have been messy fall gardeners, which we should be, we have left lots of plant material standing in place over the winter. We have done this for several reasons. We have left seedheads for overwintering and migratory birds; we have left plant litter and leaves for insect habitats (beneficial overwintering insects, food for birds); we have left perennial foliage in place to protect the crowns of plants through the cold season and to catch and hold insulating snow cover; we have left upright material for its sheer beauty sparkling with frost on a cold sunny morning.
So, first take stock. Clean and sharpen tools—pruners, loppers, shovels. Prepare a spray bottle of alcohol to disinfect pruners and loppers when pruning broken or dead branches with a clean cut. Unless you are pruning for shape or congestion, wait until after flowering to prune early flowering shrubs. Late flowering shrubs, e.g. hydrangea, buddleia, can be pruned in spring.
Be lazy about cleaning up. Wait for several days of warmer temperatures, about 10 degrees or so, to allow insects to wake up and move from their winter hiding places. Instead of cutting dead flower stalks to the ground, consider leaving 15-20 centimetres of stalk standing as nesting places for bees. They may look unsightly, but growing foliage will soon obscure them and you’ll be doing the insects a big favour. Rather than be meticulous, leave some leaf litter and small bits of dead foliage in place—again, for habitat as well as feeding the soil. Your plants will thank you.
And, despite the benefits of mulch, leave some open soil for ground nesting bees that cannot dig through inches of mulch.
Evaluate your emerging perennials for division and moving. If some plants are getting too big for your space, or you have planned to move them for reasons of aesthetics or plant association (think colour combinations, complimentary foliage, or “right plant, right place”), now is a good time to move and divide. Some perennials tend to weaken in the centre. The more vigorous growth is around the edges. Dividing these with a sharp shovel or root knife will increase your inventory and give you more vigorous plants. Some plants didn’t thrive last year? Try to figure out if they would do better in a different location.
Think about blooming times in your beds. Many gardeners strive for continuous bloom, a tricky thing to achieve. Late summer and early fall can be challenging, but many of our native plants shine then. I first have to recommend Carolina lupine (Thermopsis villosa), Blue False Indigo (Baptisia), and Bowman’s Root (Gillenia trifoliata) for sunny spots in early summer. But here are a few of my sun-loving favourites for late summer to fall:
Sneezeweed (Helenium)
False Sunflower (Heliopsis helianthoides)
Goldenrod ‘Fireworks’ (Solidago rugosa ‘Fireworks’)
Joe Pye Weed (Eutrochium purpureum)
Blue Mist Flower (Conoclinium coelestinum)
Mountain Fleece cultivars (Persicaria amplexicaulis) (non-native)
Mountain Mint (Pycnanthemum virginianum)
