Japanese knotweed: how do you get rid of it?
Why Japanese knotweed is so persistent, what Belgian law has said since 2025 and the methods that really work in a garden.
When should you trim your hedge in Belgium?
A well-trimmed hedge stays dense, healthy and at the right height. Timing is everything: too early and it grows back untidy; too late or during nesting season and you damage the hedge and disturb the birds. Here is the calendar we follow.
The two trims of the year
For most hedges (hornbeam, beech, privet, cherry laurel), two visits are enough:
- A late-winter trim, in February or March, before growth resumes and before birds start nesting.
- A late-summer trim, from mid-August to the end of September, to restore a clean shape before winter.
Respect the nesting season
From spring to late summer, hedges shelter nests. Throughout Belgium, the law protects wild birds, their nests and their eggs during the breeding season.
In the Brussels-Capital Region, the 2012 nature ordinance also prohibits felling trees and pruning them with power tools from 1 April to 15 August. For hedges, the Belgian bird protection league recommends avoiding any major trimming over the same period.
If a light trim really is needed in summer, we inspect the hedge before starting and leave any occupied section untouched.
Species that need special care
- Thuja and cypress: they do not regrow from old wood. Trim them lightly and never cut into the brown section.
- Flowering hedges (forsythia, weigela, spiraea): trim them just after flowering, otherwise you remove next year’s flowers.
- Young hedges: a formative trim right after planting helps them fill out from the base.
The details that make the difference
- Trim in a trapezoid shape, wider at the base than at the top, so light reaches the bottom of the hedge.
- Avoid frosty days and heatwaves, which stress the plant.
- Use sharp blades for clean cuts that heal better.
- Clear away the clippings: a clean hedge stays healthier.
What if the hedge has grown too tall?
A hedge that has grown too tall or too wide is cut back gradually, ideally in late winter, one side per year. This gives it time to recover without weakening. We can take care of it, with all green waste removed.
This article gives general guidance. Rules change and can differ between municipalities: always check with your municipality before starting work.
