Hedge Trimming: How to Keep Your Shrubs Healthy All Summer
Overgrown hedges don't just look untidy — they weaken your plants. These seven tips are what we use on properties across Rosedale, Leaside, and Lawrence Park every summer to keep hedges healthy and sharp all season long.
1. Trim at the Right Time — Not Just When It Looks Messy
For most Toronto hedges, two trims per year is the standard: late May or early June after the spring growth flush hardens, then again in mid-August. Skip October trimming — late-season cuts stimulate soft new growth that won't harden before the first frost, which typically hits Leaside and Lawrence Park by early November.
2. Never Remove More Than One-Third at Once
Taking off more than a third in one session stresses the plant, leaves bare woody patches, and takes years to recover. The most common mistake we see on Lawrence Park and Rosedale properties. If your hedge is significantly overgrown, plan a gradual renovation over two seasons — not a single aggressive cut.
3. Cut the Top Narrower Than the Bottom
A slight A-frame profile lets sunlight reach all the way down the plant. Hedges wider at the top shade out their own lower branches, causing die-back at the base that's difficult to reverse. This matters most for tall cedar hedges on ravine-adjacent streets in Moore Park and Rosedale.
4. Use Sharp, Clean Tools Every Time
Dull blades tear plant tissue instead of cutting it — torn tissue is a major entry point for disease, especially fungal issues that spread fast in Toronto's humid summers. Sharpen and sanitize equipment before each job. Wipe blades with diluted bleach between different plants, especially if any hedges in your area have shown signs of disease.
5. Water and Feed After Any Major Trim
Trimming stresses a plant. In the days following a significant cut, water deeply every 5–7 days. Apply slow-release granular fertilizer in early June and again in late August to maintain density and colour. Don't fertilize after Labour Day — you don't want soft new growth heading into winter.
6. Catch Brown Patches Early
Brown patches in cedar hedges usually signal spider mites, bagworms, or fungal disease — not random dieback. Spider mites thrive during hot, dry weeks in July and August, which Davisville and Lawrence Park homeowners will recognize. Catching these in June is the difference between a simple spray treatment and losing a section of hedge entirely.
7. Know When to Call a Pro
Hedges over 6 feet tall, formal topiaries, and significantly overgrown plants are best left to professionals with the right equipment. Uneven hedges are one of the most noticeable curb appeal problems on a property — and very difficult to fix once you've taken too much off one side.
Green Trail's hedge crews serve Leaside, Davisville, Rosedale, Lawrence Park, and Moore Park from June through August. Get a free site assessment.
Frequently Asked Questions
How often should I trim my cedar hedge in Toronto?
Twice a year — once in early June after the spring growth flush, and again in mid-August. A light tidy-up in late September is fine, but avoid heavy cutting after early October.
Why is my cedar hedge turning brown after trimming?
Browning within days of trimming is usually sunburn on newly exposed interior foliage. Browning weeks later points to spider mites or fungal disease. If you're unsure, we can diagnose on a site visit.
Can I trim my hedge in fall in Toronto?
Light shaping in September is fine. Avoid significant cutting after early October — new growth stimulated by a late trim can freeze before it hardens, especially in Leaside and Lawrence Park where first frost arrives by early November.
