When should you prune hydrangeas and roses?
Hydrangeas and roses are not all pruned the same way. The right time and technique for each variety, for a garden in bloom all summer.
Japanese knotweed: how do you get rid of it?
It grows very fast, creeps into cracks in paving and comes back denser every spring. Japanese knotweed is one of the most feared plants in Belgian gardens. Yet it can be contained, as long as you are patient and avoid the mistakes that spread it.
Why is it so persistent?
Its strength lies underground. Its rhizomes spread several metres around the visible clump and can stay dormant for more than ten years. A small fragment of stem or root is enough to start a new patch.
That is why occasional cutting or a pass with a brush cutter often makes things worse: it spreads the plant instead of weakening it.
What the law says
Since 7 August 2025, Japanese knotweed has been on the EU list of invasive alien species. It is forbidden to plant, sell, transport or release it into the environment anywhere in the European Union.
In Wallonia, planting it was already banned, as was dumping green waste that contains it. Municipalities can also require it to be managed.
Methods that work
- Repeated cutting: cut the stems about 10 cm above the ground, once or twice a month from April to September, for at least five years. Each cut exhausts the rhizomes a little more.
- Covering, for a small patch of less than 50 m²: a thick sheet extending 4 to 5 m beyond the patch, left in place for more than five years.
- Digging out, only for very young patches: every bit of rhizome must be removed, then the area monitored for years.
What you should never do
- Put stems or roots on the garden compost heap: they regrow.
- Move contaminated soil to another part of the garden or to another plot.
- Shred or strim the clump, which scatters fragments.
The waste must go for incineration or to an approved industrial composting facility. Check with your municipality or your intermunicipal waste company before taking it there.
How we work
We first map out the patch and check whether it extends into your neighbour’s garden. We then propose a management plan over several seasons, with regular cutting or covering depending on the area, and dispose of the waste through the right channel. It is a long-term job, and we prefer to tell you so from the start.
This article gives general guidance. Rules change and can differ between municipalities: always check with your municipality before starting work.
