Thuja (also known as Arborvitae) is definitely a fast grower! If you let your hedge maintenance slide for a season or two, it can quickly take over your yard. If yours has gotten a bit too wide for comfort, there are a few things you need to keep in mind before you start hacking away.
When is a Thuja hedge actually “too wide”?
Honestly, how wide you want your hedge is totally up to you and your personal style. Thanks to how fast Arborvitae grows, you can shape it into a slim privacy screen or a thick, bushy wall in no time. Usually, the size of your yard dictates the limit. But even though these trees handle pruning really well, you can’t just go in guns blazing with the shears—going too radical can backfire.
How to prune back an overgrown hedge
If your hedge has become a bit of a monster, you can definitely give it a significant trim to get it back in shape. To make sure your tree survives a heavy pruning, keep these tips in mind:
- Never cut back into the “old wood” (the brown, leafless interior)
- Aim for a slightly conical (tapered) shape
- Use sharp, clean tools
- Pick a cloudy, frost-free, and dry day
- If it’s a massive job, spread it out over a few years
The golden rule with Thuja is that it won’t grow back if you cut into the old wood. By pruning it into a conical shape—meaning the bottom is slightly wider than the top—you ensure the whole plant gets enough light and air. This also helps prevent the plant from turning brown on the inside. Be careful with the weather, too; direct sun on fresh cuts can cause brown tips, while too much moisture can lead to fungal diseases.
Even though Arborvitae is tough, a radical “haircut” is stressful for the plant. If you haven’t touched the hedge in years, it’s better to do the work in stages over two or three seasons. Always try to take an even amount off all sides, and don’t forget to thin out any tangled or overgrown inner branches to improve air circulation.
When is the best time to trim a Thuja hedge?
If you’re planning a major cutback, the best time to do it is in early spring before the new growth starts. Just a heads-up: to protect nesting birds, it’s best to do your heavy pruning between October and February. During the spring and summer months, stick to light touch-ups and minor corrections only.
