Who must control noxious weeds on a BC property?

What the answer means

The Weed Control Regulation names the noxious weeds: some everywhere in BC, others only in the regional districts listed beside them. A report lists the invasive plants the Province has recorded on the lot and within 100 m, and marks the ones that are noxious there.

Whose duty

An occupier must control the noxious weeds growing on land and premises it occupies, and on property on them (Weed Control Act s. 2). The occupier is whoever is in physical possession of the land, or is responsible for and controls its condition and use; there can be more than one, and a council or the Province can be one (s. 1). The Province occupies unoccupied Crown land and provincial highways outside a town's care (ss. 12, 13).

What a noxious weed is

The regulation designates 39 weeds noxious throughout BC, Japanese and the other knotweeds, giant hogweed, spotted and diffuse knapweed and gorse among them, and adds others in the regional districts named beside them (Weed Control Regulation s. 2, Schedule A). Seeds count too (Act s. 1). The table below lists them.

An inspector's notice

An inspector may enter land in daylight, but not a residence, to inspect it (s. 3), and serve a notice directing the occupier to control the noxious weeds; an occupier who is served must promptly tell the owner (s. 4). A council can appoint its own weed control officers (s. 10).

If it isn't done

If the weeds aren't controlled in the time the notice gives, at least 5 days, or as it says, or if it's needed at once to stop them spreading, an inspector may enter and control them. Every occupier is then liable for the certified cost (s. 7), and unpaid, it goes on the tax roll as taxes in arrears in a municipality, or as delinquent taxes outside one, collected as taxes are (s. 8). Knowingly breaking the Act, or ignoring a notice, is an offence (s. 15).

Moving soil, machinery and seed

A vehicle with knapweed on it, and farm equipment, construction machinery, an RV or a horse trailer carrying any noxious weed, may not be moved on a highway; farm equipment must be cleaned of noxious weeds and their seeds before it leaves the land it worked; and where a noxious weed isn't established, no one may apply or sell topsoil, fertilizer or lime holding it or its seeds (Weed Control Regulation ss. 6 to 8).

What the report shows

The Province's invasive plant records on the lot and within 100 m of its line, each species with its records and latest date, marked where it's noxious in the lot's regional district. The records come from surveys, mostly since 2022 and along roads, trails and shores, so none recorded doesn't mean none there, and a plant recorded may since have been treated.

What it means for a buyer

A noxious weed on the lot is the new owner's to control from the day they take possession, and some, the knotweeds above all, take years of treatment (our reading). Ask the seller what has been found and what was done, and price any treatment in.

Our summary of the Weed Control Act (RSBC 1996, c. 487) and the Weed Control Regulation (B.C. Reg. 66/85, Schedule A), read on BC Laws 2026-10-19. How to treat a plant, and which herbicides may be used where, are rules of their own: ask the local government or a licensed applicator.

Sources, read 2026-10-19 and summarised in our words unless marked otherwise: Weed Control Act, RSBC 1996, c. 487 (ss. 1 to 4, 7, 8, 10, 12, 13, 15); Weed Control Regulation, B.C. Reg. 66/85 (ss. 2, 6 to 8, Schedule A); Invasive Species Observations (InvasivesBC), Province of BC (Open Government Licence – British Columbia).

Before you buy: who to ask

The seller or their agent

Have knotweed, hogweed or other noxious weeds been found here, and what was done about them? Has an inspector served a notice to control weeds on this land?

The local government

Does the council have a weed control officer or an invasive plant program here, and are any weed control costs on this property's taxes?

See also species at risk, cutting trees and what a seller must disclose.

Noxious weeds by regional district

39 weeds are noxious everywhere in BC (Part I of Schedule A): Annual Sow Thistle (Sonchus oleraceus), Bohemian Knotweed (Fallopia x bohemica), Bur Chervil (Anthriscus caucalis), Canada Thistle (Cirsium arvense), Common Crupina (Crupina vulgaris), Common Reed (Phragmites australis), Common Toadflax (Linaria vulgaris), Dalmatian Toadflax (Linaria dalmatica), Dense-flowered Cordgrass (Spartina densiflora), Diffuse Knapweed (Centaurea diffusa), Dodder (Cuscuta spp.), English Cordgrass (Spartina anglica), Flowering Rush (Butomus umbellatus), Garlic Mustard (Alliaria petiolata), Giant Hogweed (Heracleum mantegazzianum), Giant Knotweed (Fallopia sachalinensis), Giant Mannagrass (Glyceria maxima), Gorse (Ulex europaeus), Himalayan Knotweed (Polygonum polystachyum), Hound's-tongue (Cynoglossum officinale), Japanese Knotweed (Fallopia japonica), Jointed Goatgrass (Aegilops cylindrica), Leafy Spurge (Euphorbia esula), Milk Thistle (Silybum marianum), North Africa Grass (Ventenata dubia), Perennial Sow Thistle (Sonchus arvensis), Purple Loosestrife (Lythrum salicaria), Purple Nutsedge (Cyperus rotundus), Rush Skeletonweed (Chondrilla juncea), Saltmeadow Cordgrass (Spartina patens), Scentless Chamomile (Matricaria maritima), Smooth Cordgrass (Spartina alterniflora), Spotted Knapweed (Centaurea maculosa), Tansy Ragwort (Senecio jacobaea), Velvetleaf (Abutilon theophrasti), Wild Oats (Avena fatua), Yellow Flag Iris (Iris pseudacorus), Yellow Nutsedge (Cyperus esculentus) and Yellow Starthistle (Centaurea solstitialis).

Part II adds weeds that are noxious only in the regional districts named beside them. Districts are listed by name, not ranked.

From Schedule A of the Weed Control Regulation on BC Laws, with the regulation's names, a few shortened, and its misspelt "Sinapsis" read as Sinapis. The Northern Rockies Regional Municipality and the Stikine Region aren't in a regional district: Part I applies there. A report marks each plant the Province has recorded on or near a lot that is noxious there.