British Columbia

Pulling out invasive weeds? Don't put them in the compost bin

Invasive plants that end up in the compost could take root wherever the compost is later spread, the Capital Regional District says.

Invasive plants should be bagged and taken to landfill for proper disposal, officials say

Knotweed, seen here sprouting through pavement, is among the invasive plants officials in the Capital Regional District are concerned about. (

Knotweed. Giant hogweed. Blessed milk thistle. These are just some of the dreaded plant species the Capital Regional District is trying to eradicate.

But if you're cleaning up your yard this spring and come across one of these invasive weeds, officials say you should avoid putting them in your compost bin.

The heat involved in the compost process is not enough to kill the seeds of invasive plants, said Glenn Harris, senior manager of environmental protection for the Capital Regional District.

As a result, invasive plants can spread when the compost material is reused elsewhere.

"They go from isolated spots, to next thing you know they are being distributed through various pathways, and all of a sudden they are starting to be a real issue," Harris said.

Invasive plants are a concern because they pose an environmental and economic risk to local ecosystems. They can displace native species and disrupt infrastructure.

Giant hogweed. (CBC)

'Trying to raise awareness'

Rules on what goes into compost are set by local bylaws.

When it comes to invasive species, municipalities look to a provincial list of weeds of concern, Harris said.

The CRD voted Wednesday to ask the province to update its list to add new regional invasive plants.

"We are trying to raise awareness about which species are a concern and then what is the proper disposal method," Harris said.

Work to determine how many invasive weeds end up in with the compost is in the early stages, he said.

Gardeners who think they have pulled one from their yard should put it in a bag and take it to the Hartland Landfill for proper disposal.

The CRD has also started distributing alert sheets to help people identify invasive species in their yard.