As the days grow shorter and the air turns crisp, the vibrant greens of summer slowly transform into the warm reds, oranges, and yellows of trees in autumn. It’s a sight that makes Ontario neighbourhoods look like postcards, but behind the beauty lies an incredible bit of plant science and some important seasonal work for homeowners. After the very dry summer and early fall we’ve had, watering your trees before the ground freezes is especially important to help them stay strong through the winter.

Why Leaves Change Colour in the Fall

All summer long, leaves are hard at work making food for trees. Chlorophyll, the pigment that makes them green, captures sunlight and turns it into energy in a process called photosynthesis that helps trees grow, store sugars, and thrive.

But once autumn arrives, the days get shorter and there isn’t enough sunlight to keep photosynthesis going. Trees stop producing chlorophyll, and as the green fades away, the pigments hiding underneath finally get their moment to shine. Carotenoids bring out the golden yellows and oranges, while anthocyanins add the deep reds and purples.

It’s more than just a show for trees in autumn, it’s a survival strategy. Trees reabsorb nutrients from their leaves before dropping them, conserving resources to carry through the winter months.

How Trees in Autumn Drop Leaves to Prepare for Winter

Falling leaves are part of a bigger plan. By shedding them, trees reduce water loss and protect themselves from frost and heavy snow. Without leaves, they conserve moisture and avoid breakage from icy buildup. Many trees also enter dormancy, a winter “rest mode” that helps them save energy until spring. It’s nature’s way of making sure trees survive and thrive year after year.

Managing Fallen Leaves in Your Yard

While trees in autumn are gorgeous, the colourful leaves can be a lot less charming once they blanket your lawn. In Ontario, the best practice is to put those leaves to good use rather than bagging them all for disposal.

Chop them into tiny pieces with a mulching mower and they’ll act as a natural fertilizer for your lawn. You can also use shredded leaves as a protective mulch around tree roots and garden beds to insulate against frost. Composting is another eco-friendly option, turning yard waste into nutrient-rich soil, which you can do yourself or through municipal seasonal leaf collection where available.

When to Stop Watering Your Trees in Autumn

One of the most overlooked steps in fall tree care is watering. Even though the weather is cooler, trees still need plenty of moisture to get through the winter, especially after a really dry summer. A deep soak in the fall helps trees store water in their root systems, giving them the strength to survive freezing temperatures.

In Ontario, you should continue watering until the ground is frozen and a shovel can no longer break the soil. Pay extra attention to young or newly planted trees, since their roots aren’t as established, and to evergreens that keep their needles year-round and lose moisture all winter long.

The goal is to water deeply but less often, encouraging roots to grow downward. Setting a hose to a slow trickle at the base of a tree for 30–60 minutes once a week is far more effective than frequent light watering. Once the ground is solidly frozen, it’s time to shut off outdoor water and disconnect hoses for the season.

Get Your Trees Winter-Ready with Professional Help From J&C Tree Services

Caring for trees in autumn isn’t just about raking leaves. It’s about making sure your trees are set up to handle the stresses of winter—snow, ice, wind, and freezing temperatures. That means checking for dead or weak branches that could snap in a storm, making sure young or newly planted trees get enough water, and protecting roots with proper mulching.
This is where professional tree services can make a real difference. At J&C Tree Services, we have the training and equipment to safely prune branches, assess tree health, and prepare your property for whatever winter throws at it. A fall checkup ensures your trees aren’t just beautiful in autumn, but also strong, safe, and ready to thrive again in the spring. You can contact us at 416-997-7280 or send us an email at info@JandCTreeService.com.