Throughout the summer, you nurture your garden with care, hoping it flourishes. However, when the chill of winter arrives, it seems as if all your diligent efforts have been diminished by the withering leaves. Yet, there are straightforward, expert-endorsed activities you can undertake now to ensure your perennials wind down correctly, ready to burst forth anew with a vibrant spring bloom.
Nicole Johnsey Burke, a gardener and CEO of Gardenary Inc., advises that perennials should enter a state of dormancy during this period, avoiding the production of delicate leaves that will only freeze over. “In my own garden, I concentrate on gradually slowing things down as the temperatures drop,” she explains. “It’s all about timing and understanding your plants.”
For those who prefer a low-maintenance method (and are crossing their fingers), Burke has some encouraging news: “Frankly, with quality soil and a layer of nutrient-rich compost, many resilient perennials will be just fine on their own.” But if you’re aiming for a lush return when the warmth resumes, continue reading for additional steps you can take.
Nicole Johnsey Burke, Gardener and CEO of Gardenary Inc.
Stop using fertilizer! “At this stage of the season, you don’t want to stimulate an abundance of new, leafy growth that will simply be destroyed by the first frost,” Burke advises. Instead, she suggests concentrating on cultivating healthy soil that will provide your plants with what they require without overexerting them. Burke favors the natural method, incorporating organic worm castings, leaf mold, or coffee ground compost.
“This is an easy trick that actually makes a difference,” Burke comments on watering before a frost is anticipated. “Moist soil retains heat better than dry soil, so when temperatures plummet overnight, the additional moisture acts as a small heat battery, releasing warmth and safeguarding the roots.”
She points out that this method won’t ward off a severe freeze, but it can make the difference between damaged and undamaged leaves following a light frost. Aim for soil that is evenly moist, not waterlogged.
You might be tempted to grab your pruning shears and start cutting, but that’s not always the best course of action. For most herbaceous perennials, Burke prefers to wait until late winter or early spring for any significant pruning. “That old growth can aid the plant in surviving the winter and can even serve as a food source for birds,” she explains.
Her exceptions are any plants that are visibly diseased or dead. “Feel free to remove those; otherwise, I prefer to let the plants be,” she notes. “Nature has its own rhythm, and sometimes the best thing we can do is step back and let it unfold.”
For ornamental perennials, particularly in beds, Burke advocates for a mulch layer to shield the roots from extreme temperature fluctuations, but it’s not necessary to rush this step. “Wait until after your first hard frost to apply mulch,” she advises. “If you apply it too early, you can trap in too much warmth or moisture, potentially encouraging diseases.”
Regarding vegetables, Burke takes a different approach. Skip the mulch and instead apply a layer of fresh, nutrient-rich compost, as wood mulch can bind nitrogen and compete with your vegetables for nutrients.
“Here’s the deal: Not all plants require frost cover, though many benefit from it,” Burke states. When overnight temperatures drop into the 30s, ensure that any tender plants, like lettuces, softer herbs, and peppers, are covered.
For more moderate and severe freezes (below 28°F), Burke recommends using a frost cloth layered over a light sheet or tarp, but cautions against improper placement. “The most common mistake I see is people simply placing a cover directly over their plants,” she cautions. “Please don’t do that! You want space between the plant and the cover. Use hoops, cages, or even sticks to create that space above your plants.”
Options like frost cloths or floating row covers are breathable and allow light in while still insulating. Old sheets and towels can be used in a pinch and for shorter periods, but they can be too heavy and trap moisture, so use them wisely and remove them during the day.
If your perennials are primarily in pots, your wintering technique will be slightly different. Burke recommends relocating potted or tender perennials (such as rosemary and peppers) indoors before the first hard frost to protect their roots from the cold.
“Even a garage or enclosed porch can suffice if you lack indoor space,” she observes. “Just ensure there’s some light and temperatures remain above freezing.” For more robust plants in pots, Burke enjoys grouping them in a sheltered area near an exterior wall or in a corner.
To go the extra mile, consider wrapping pots in burlap or old blankets to insulate the root area. “You can also place them on a piece of foam or straw to prevent the cold from seeping up from below,” she suggests. It’s better to be safe than sorry!
