Is It Too Late To Plant Trees and Perennials in Ontario?
As the days grow shorter and the air colder, you may be wondering Is it too late to plant trees and perennials in Ontario? The good news is that, in most cases, the answer is a reassuring no (with some caveats and exceptions). Fall is actually one of the best times to get plants into the ground, as long as you’re mindful of the timing and preparation. Let’s dig into the details.
Why Fall Planting Works
Fall planting in Ontario has several benefits:
Cooler Temperatures
Plants experience less stress from heat, making it easier for them to establish roots.
Moisture Levels
Autumn rains are ideal for consistent soil moisture, giving roots the hydration they need.
Extended Root Development
Trees and perennials focus their energy on root growth instead of foliage during cooler months, helping them settle in before winter.
How Late Is Too Late?
Timing is everything. In Ontario, the general rule is to plant trees and perennials at least a few weeks before winter sets in and the ground stays frozen. Just be sure to water the trees well. This gives roots enough time to get established.
For Trees
Aim for mid-September to late October. Evergreens are best planted earlier in the season, as they need more time to anchor their roots before winter (water well and wrap evergreens with burlap to prevent drying out of the needles).
For Perennials
You can plant most varieties into early November if the weather cooperates and the soil remains workable. Small perennials may get lifted in the winter with frost. So, make sure you check the plants in early Spring and replant if needed.
Keep an eye on local frost dates and avoid planting when the ground is too hard or excessively wet.
Choosing the Right Plants
Certain trees and perennials are better suited for fall planting:
Trees
Maples, oaks, and elms are hardy choices. But really, any tree that’s hardy in zone four or lower can be planted right up until heavy frost. See the Canadian hardiness zone map.
Perennials
Hostas, daylilies, and peonies establish well in the fall. Native plants are also a great option for added resilience.
Pro Tips for Success
Prep the Soil
Remove weeds, loosen the soil, and add compost or mulch to enrich it.
Water Thoroughly
Even though the air is cooler, trees and perennials still need regular watering after planting.
Protect Your Investment
Add a layer of mulch to insulate roots and consider using tree guards or burlap to protect young trees from frost and wildlife.
What About Spring Planting?
If you’ve missed the window for fall planting, don’t worry. Spring is another excellent time to plant. However, fall offers a head start, especially for trees and perennials that can handle Ontario’s winter conditions.
It’s not too late to plant trees and perennials in Ontario—but act quickly! With the right care and timing, your new additions will have a strong foundation to thrive next year. So grab your shovel, bundle up, and get planting before winter truly settles in! If you’d rather save planting for the spring and want some expert assistance, contact us.
Initial Watering: Immediately after planting or transplanting, water the tree thoroughly. This helps settle the soil and eliminate air pockets around the roots.
When to Fertilize: Avoid fertilizing immediately after planting. Wait until the tree shows signs of new growth, which indicates it has begun to establish its roots.
Staking: Young trees may need to be staked to protect them from strong winds, especially in exposed areas. Use flexible tree ties that allow some movement, promoting a stronger trunk.
Frost Protection: In areas prone to frost, new 
Japanese beetles were introduced from Japan in the early 20th century and have since made themselves at home in Southwestern Ontario. These beetles have a metallic green color with copper-colored wings and are often found munching on the leaves of roses, grapes, and fruit trees.
Aphids are native to North America and thrive in our temperate climate, reproducing rapidly and infesting a wide range of plants. This makes Aphids one of the most common among the common lawn and garden pests in our region. Look for clusters of small, green, pear-shaped insects on plant stems and new growth of various garden plants, including roses, vegetables, and fruit trees.
Native to Asia, emerald ash borers arrived in North America in the early 2000s and have devastated ash tree populations. Look for D-shaped exit holes in ash tree bark, canopy dieback, and S-shaped larval galleries under the bark.
Spider mites are native to North America and thrive in warm, dry conditions, rapidly infesting plants. Look for fine webbing on the undersides of leaves and stippling or discoloration on foliage of garden plants, including tomatoes, beans, and ornamentals.
These soil-dwelling larvae are the immature stage of beetles like Japanese beetles, and they primarily feed on grass roots. Look for patches of dead or dying grass, which may indicate white grub infestation.
Cutworms are native to North America and are nocturnal pests that feed on young seedlings at or below ground level. Look for seedlings that have been cut off at the base.
Slugs and snails are native to the region and are nocturnal pests that feed on plant foliage and tender shoots of a range of garden plants. Follow slime trails and look for irregular holes in leaves.
Cabbage worms are native to North America and are the larval stage of small white butterflies. As their name implies, they feed on brassica crops. Look for green caterpillars on cabbage family plants (cabbage, broccoli, kale), causing chewing damage to leaves.
Thrips are native insects that feed on the sap of garden plants, including roses, onions, and peppers. They can transmit diseases to a wide range of plants. Look for tiny, slender insects and silvery patches on leaves.
Scale insects are native to North America and can weaken or kill plants by feeding on sap and excreting honeydew of ornamental and fruit-bearing trees. Look for small, immobile insects on stems and leaves, often surrounded by a protective shell.
The soils in Southwestern Ontario are diverse, shaped by various factors including climate, parent material, and topography. Common soil types include clay, loam, and sandy soils. Each soil type has unique characteristics that affect water retention, drainage, and nutrient availability.
Selecting the appropriate plants for your soil type is crucial for a thriving landscape in Southwestern Ontario:
Homeowners in Southwestern Ontario can proactively improve soil conditions to meet their landscaping needs. Here are some suggestions:
Japanese Maple
Boxwood
Rhododendrons and Azaleas
Compact Hydrangea
Assessment and Safety Considerations
Fertilization and Hydration