Himalayan blackberry: how to get rid of it for good in Washington and Oregon

This is the full blackberry guide. The site’s brush clearing guide for Washington and Oregon compares Himalayan blackberry with Scotch broom, English ivy and holly, and once a patch covers a slope, a fence line or most of a lot, the job becomes land clearing, with permit questions this page flags near the end.

King County’s weed program describes Himalayan blackberry as far bigger and more imposing than the native trailing blackberry: plants up to 15 feet tall, canes that can pass 40 feet, and seeds carried off by birds and other animals. Its native range is Eurasia; in the county’s words it “has escaped cultivation” and become one of the most widespread plants in the landscape.

Is Himalayan blackberry invasive in Washington and Oregon?

Yes, and both states list it as a noxious weed. The Washington State Noxious Weed Control Board made it a Class C weed in 2009. Class C weeds are already widespread, and each county decides whether to enforce control; King County, for one, lists it as non-regulated, so owners there are not required to remove it, though the county encourages it. Washington’s plant quarantine list, which bans the sale of listed plants, does not include it (WAC 16-752-610).

Oregon puts Armenian (Himalayan) blackberry on the Oregon Department of Agriculture’s B list: weeds of economic importance that are regionally abundant. The weed board and ODA call it Rubus armeniacus; King County now uses Rubus bifrons for the same plant.

How to tell Himalayan blackberry from other blackberries

Three blackberries ramble across lots west of the Cascades, and only one of them is native. The quickest check is the underside of a leaf: Oregon State University’s landscape plant database describes Himalayan blackberry leaflets as dark green and somewhat glossy on top, gray-green and softly hairy underneath.

Sources: Washington State Noxious Weed Control Board (Himalayan and evergreen blackberry); King County Noxious Weed Control Program; OSU Landscape Plants (Rubus armeniacus, R. laciniatus, R. ursinus); ODA Noxious Weed Policy and Classification (2025); all checked 2026-10-02.

Leave the native one alone. Trailing blackberry stays low, its thin stems run along the ground, and most plants are either male or female, so only some carry fruit (OSU). Evergreen blackberry gets the same treatment as Himalayan: Washington lists both as Class C, and King County gives both the same control advice, though Oregon’s list names Armenian blackberry and not the cutleaf species.

Why blackberry bushes keep coming back: the root crown

A blackberry patch is mostly underground. Each plant grows from a root crown that King County describes as large, starchy and oddly shaped, with sprawling roots, and the state weed board says the plant spreads by seed and also by resprouting rootstalks, rooting stem tips, and fragments of root and stem.

King County’s February 2026 blackberry BMP adds the numbers: main canes up to 10 feet long, trailing canes up to 40 feet, and up to 520 canes per square meter, about 48 per square foot. The weed board adds that burning will not kill the roots.

How to get rid of blackberry bushes: methods that work

Every method that works goes after the root crown, either by digging it out or by starving it with repeated cutting. King County’s BMP is plain about the second route: several cuttings a year over several years are needed to exhaust the roots’ food reserves.

Sources: King County Noxious Weed Control Program (Himalayan blackberry page, blackberry BMP February 2026, weed control practices); Washington State Noxious Weed Control Board; WAC 173-425-040; checked 2026-10-02.

Himalayan blackberry removal, step by step

1. Dress for the pricklesThe canes carry hooked prickles with thick bases (weed board). Heavy gloves, long sleeves, long pants and eye protection.
2. Cut the canes to about a footLoppers or pruners do it (King County BMP). The weed board leaves a foot of stem so you don’t lose track of the plant.
3. Clear room to digPull the cut canes back with a rake or another tool (weed board).
4. Dig out the crownUse a mattock, claw mattock or pulaski (weed board; King County BMP). Take the main root ball and as much of the spreading side roots as possible.
5. Get the debris off the groundCanes and crowns left on soil can keep growing; see disposal below.
6. Come back for resproutsCut, pull or dig new shoots through the following seasons, and replant the cleared ground.

Goats, mowing and covering

Mowing and goats are cutting by other means, so they work the same way: often, and for years. King County’s BMP says goats can control regrowth one to four years old but mostly strip leaves on mature canes, and grazing has to continue. Once the crowns are out, its general weed guidance smothers new growth with cardboard or newspaper under 6 to 12 inches of heavy mulch.

The same label rules apply to a cut stump that keeps sprouting; that job is covered in how to kill a tree stump.

When to tackle blackberry: rain, flowering and nesting season

Dig when the ground is soft. King County’s BMP says manual control works best after rain or in loose soil, which west of the Cascades means the months after the fall rains return. NOAA’s 1991–2020 climate normals put 83 percent of Seattle-Tacoma’s yearly precipitation in October through April, and 82 percent of Portland’s.

Source: NOAA NCEI 1991–2020 monthly normals, Seattle-Tacoma International Airport (USW00024233) and Portland International Airport (USW00024229), months summed by Westcoast-Tree.org; checked 2026-10-02.

If you can cut only once a year, King County says to cut when the plants begin to flower. Herbicide work, if you choose it, belongs in late summer to fall, as above.

Then there are the birds. King County’s BMP suggests holding off on large blackberry removal projects during nesting season, which it puts at mid-March to the end of June, and on sites that matter as bird habitat, removing only a quarter of the patch each year, especially where there is little other habitat nearby. The federal rules on active nests are summarized in the best time to cut down a tree.

What to do with blackberry canes and root crowns

Blackberry debris can grow back, so it has to dry out or leave the site. King County’s guidance:

Burning rarely fits. The weed board allows that plants can be burned back, with any needed permits, but says fire will not kill the roots, so follow-up control is still needed. In Washington, residential and land-clearing burning is not allowed in urban growth areas or in cities over 10,000 people (WAC 173-425-040), and Oregon DEQ says bans depend on where you live, with cities, counties and fire districts adding their own. Check Washington yard debris burning rules or Oregon yard debris burning rules before lighting a pile.

One Oregon wrinkle: the state quarantine rule lists transport among its prohibitions, so before you haul a trailer load off site, ask your hauler or county weed program how they want blackberry delivered.

Replanting, slopes and when to hire a crew

Bare ground invites the next crop of seedlings. King County’s BMP says large cleared areas need to be stabilized and revegetated with native or non-invasive plants to prevent erosion and re-invasion: replanted and mulched, or reseeded with a suitable grass. Thickets also shut out sun-loving natives such as Pacific madrone and Douglas fir, so clearing gives them room. Expect to check for resprouts for several years. Near a house in wildfire country, the cleared strip also counts toward your defensible space.

Hiring makes sense for a patch on a slope, tangled into a fence or trees, or too big to dig by hand in a season. Brush clearing is priced by the hour, and this site models a three-person crew at about $225 per crew-hour in Oregon and $210 in Washington (modeled estimate, not quotes; method). Ask whether a quote includes a return visit for resprouts, since the follow-up is what makes the first visit last.

Slopes and streams change the job. King County’s BMP says extra permits may be required for blackberry control in riparian areas, asks for methods that disturb as little soil as possible in critical areas, and rules out mowing where soils are very wet or prone to compaction or erosion. Critical-area rules and the permits that come with clearing are on the land clearing hub.