In the fall, we’re often focused on looking up at the changing leaves, and we miss what’s going on closer to the ground. As temperatures drop, perennial plants in our gardens prepare to go into a dormant stage for the winter. With climate change bringing more fluctuating temperatures, particularly through winter, be sure to add mulch on top of the soil underneath your plants to help keep them insulated, preserving biodiversity and building climate resilience in your yard.
Understanding Plant Dormancy
Why Plants Go Dormant
Dormancy allows plants to rest and repair as they get ready for the next year. While they’re dormant, plants conserve energy to help protect themselves from harsh winter conditions. Think of it like a nice, long nap.
How Dormancy Works
Hormones in plants are triggered when days become shorter and temperatures cool. These hormones tell the plant to slow down photosynthesis and respiration. The energy that once went into keeping the above-ground parts of the plant alive moves into the roots, storing carbohydrates and other nutrients to help the plant survive the winter.
What Dormancy Looks Like
The leaves of most native perennial plants turn brown and wither, but there are a few that get stunning fall colours first, such as foxglove beardtongue, which turns bright red like in the feature photo. Some plants keep old stems standing with seedheads ready to feed the birds. Others, like common sneezeweed, maintain some green leaves above at ground-level. Though dormant plants may look dead, if you check the roots, they will be white and healthy-looking.
Caring For Your Yard
Getting your Garden Ready for Winter
As your plants move into their dormant stage, there are a few tasks you can do around your garden to get it ready for winter. Use this checklist to make sure your garden is ready:
- Prune trees and shrubs and refrain from cutting back perennial wildflowers.
- Divide overgrown clumps of native perennial wildflowers into smaller clumps to plant throughout your garden or share with neighbours.
- Continue to water newly planted trees and shrubs until the ground freezes. This is especially important for evergreens to prevent their needles from drying out and turning brown during the winter.
- Spread fallen leaves into your garden. This protective layer of leaves will insulate dormant plants, prevent frost heaves from uprooting recently planted perennials and provide over-wintering habitat for beneficial insects.
Storing Your Tools
Once your garden checklist is complete, make sure you put your tools away for the winter. Use this checklist to help keep your garden tools in good shape for next season:
- Clean and sharpen pruners to prevent rust and to keep pruning cuts clean.
- Clean and lubricate shovels to prevent rusting.
- Disconnect and drain hoses to prevent trapped water from freezing and splitting the hose.
- Hang rakes and other garden tools on a hook in a dry location, such as a garden shed, to keep them away from the elements.
Keeping your perennials healthy will help build biodiversity and climate change resilience – in your own neighbourhood!
Plant of the Month
Common Sneezeweed
Helenium autumnale
Despite its name, common sneezeweed doesn’t make people sneeze. Instead, this late-blooming perennial brings golden colour to gardens throughout the fall season. You can even clip a few stems to bring some sunshine indoors.
Butterflies visit the flowers for nectar, including monarchs that need a boost of energy to make their long journeys to Mexico. As they get ready for winter, some bumblebees collect pollen which readily sticks to their furry bodies. Rabbits and deer tend to leave this plant alone because of its bitter taste and toxicity.
Care Notes
A clump-forming plant, common sneezeweed blooms for four or more weeks. Its flowers have globe-shaped centres that are surrounded by vivid yellow ray florets. These florets look like petals but are actually individual flowers.
By the time it has flowered, the ground-level basal leaves will have mostly faded, but the winged stems and narrow, pointy leaves hang on until the first frost. As the plant begins to enter its dormant phase, some energy is moved into creating new basal leaves. This crown survives winter and is where you will find new growth the following year.
In late-spring, trim the plant to keep it bushier and in the fall, leave the faded flower heads to spread their seeds and feed the birds. As short-lived perennials, clumps need dividing in spring every few years to keep the plants vigorous and flowering.
Sun and Rain
Common sneezeweed prefers moist to wet, sunny areas. Plant alongside other moisture-loving plants such as swamp milkweed, great blue lobelia and New England aster. Consider planting Joe-Pye weed behind common sneezeweed for a taller background along a fence, wall, or property line. For more ideas, consult our native plant lists.