While spring brings the excitement of new growth, autumn is where next year’s garden success is built! Fall prep sets your plants up for winter survival, builds healthier soil, and gives you a massive head start when spring arrives.
What to Prune (And What to Leave Alone!)
Pruning in autumn requires a light touch: pruning too heavily or at the wrong time can stimulate new growth that gets killed off by cold weather.
Prune Dead, Diseased, or Damaged Branches. Remove these anytime to prevent winter winds from snapping them or spreading disease. Remember to dispose of these cuttings in yard waste bags and to sterilize your pruners with rubbing alcohol before using them again on healthy plants!
Prune back Perennials with Diseased Foliage. Cut back plants prone to powdery mildew or visible pests once the foliage dies back after a hard freeze. If you notice that the perennial foliage becomes matted or soggy, you should prune back to ensure water can still get to the roots.
Prune back Crossing or Rubbing Branches: Clean up structural branch issues on mature trees while leaves are off and branch shapes are visible. There are some exceptions to this rule, so be sure to read below!
What to LEAVE Until Spring:
Leave Spring-Blooming Shrubs Alone! Don't prune lilac, forsythia, azalea, or rhododendron now, or you'll cut off next year's flower buds! Broken or diseased branches are the exception to this rule, as you want to ensure that the plants go into their winter dormancy with the most amount of energy to flourish in the spring.
Leave Evergreens & Conifers Alone! Avoid major pruning late in the season, as fresh cuts won't heal before freezing temperatures arrive. The best time to prune evergreens are after they have fully pushed out new growth in the spring and summer, usually around the end of June.
Successfully Protect & Wrap Trees and Evergreens
Ottawa winters bring harsh winds, heavy snow loads, and freeze-thaw cycles. Protecting young trees and sensitive evergreens now prevents winter burn and animal damage. We have a helpful handful of tips to ensure your evergreens and trees are protected properly!
Use Burlap or Breathable Fabrics When Shielding Evergreens:
New evergreens can benefit from a light, protective windscreen in the winter. This is similar to wearing a windbreaker or sunscreen to protect the water content in the outer needles. Burlap screens protect sensitive foliage (like cedars, boxwoods, and rhododendrons) from drying winter winds and road salt spray.
Insert 3–4 wooden stakes around the plant to create a frame, then wrap burlap around the outside. Secure with twine. Avoid letting burlap touch the outer needles directly where wet snow can cling. If you wrap an evergreen too tightly, you risk damaging branches, obstructing airflow, and trapping moisture which can lead to diseases and pests in the spring.
Use Trunk Guards On Young Trees:
Remember that white plastic spiral you got when you bought a tree from us? This simple tool prevents sunscald (bark splitting from rapid freeze-thaw cycles) and bark from hungry mice, voles, and rabbits. Every spring, we see lots of pictures of trees who have become victims to being voraciously girdled by winter foragers, and it is one of the most common reasons trees fail to thrive in the spring.
Wrap white plastic spiral tree guards or corrugated drainage pipe around the trunk from the base up to the lowest branch. If there is a heavy snowfall, you can add more plastic tree guards around the trunk or branches.
Smart Autumn Gardening Tips
Shred & Mulch Your Leaves! Don't bag your fallen leaves! Mow over them to break them down into a nutrient-rich leaf mulch. Spread a 2–3 inch layer over garden beds to insulate roots and enrich soil biology. If you plant sensitive shrubs like hardy figs or floribunda roses, you can use healthy leaf mulch and peat moss to help insulate rose huts and burlap screens.
Leave Seeding Perennials for the Birds: Hold off on cutting back native perennials with seed heads (like coneflowers, black-eyed Susans, and sunflowers). They provide vital winter food for goldfinches and chickadees! Save on birdseed this winter by leaving the natural seeds available.
Leave Ornamental Grasses Tall: Keep tall grasses standing through winter. Their golden movement adds beautiful winter interest to your landscape while crown foliage insulates the roots from deep freezes. Grasses that have gone to seed also provide a food source for hungry garden friends.
Water Until the Ground Freezes: Evergreens and new plantings need plenty of moisture stored up before the soil freezes solid to prevent winter desiccation. This last watering helps give energy in the spring and can better insulate against harsh frosts and freezes.