Kochia (Summer Cypress) or Burning Bush? The Red-Fall Annual That Is a Noxious Weed in Washington, Oregon and Arizona

Kochia (Bassia scoparia) is a fast-growing annual grown as summer cypress or burning bush for feathery foliage that turns red in fall. It is also a weed: Washington, Oregon and Arizona list it as noxious, and one plant typically sets about 14,600 seeds that scatter when the dry stem tumbles. It dies at the end of the season and returns only from seed.

That mix of garden plant and weed is why the advice online contradicts itself. Below: how to identify kochia, what it does through the year, how to grow it if your state allows it, how it differs from the shrub that shares its “burning bush” name, which states list it (I checked every state list I could open, one by one, and claims of a long Western list did not hold up), and what extension sources say about herbicide resistance and livestock.

Kochia, Summer Cypress and Burning Bush: One Plant, Several Names

They are one species. The USDA PLANTS Database accepts the name Bassia scoparia, gives “burningbush” as its common name, and adds kochia, Mexican fireweed, mirabel and mock cypress. Washington’s noxious weed quarantine rule lists it as “Bassia scoparia (syn. Kochia scoparia)” with the common names “kochia, summer-cyprus, burning-bush, fireball, Mexican fireweed.” Older garden and weed literature uses Kochia scoparia, so search both names.

It arrived on purpose. Oregon’s agriculture department says kochia was introduced to the United States around 1900 as an ornamental from Eurasia, and that its bright red fall foliage attracts gardeners’ attention. Washington’s invasive species fact sheet likewise describes a garden ornamental introduced in the early 1900s. That history explains kochia’s odd position today: a plant introduced for gardens that Washington and Oregon now restrict for sale.

Three pre-planned garden beds, free

Stop staring at empty beds: printable plans with exact layouts, plant lists and planting calendars — yours free from the Garden Library.

Send me the plans

I agree to receive emails from Blooming Expert and accept the Privacy Policy. Unsubscribe anytime.

How to Identify Kochia

Look for soft, hairy, lance-shaped leaves on an upright, many-branched annual that turns reddish in autumn. The seedling stage is the most distinctive, and the table below pulls the features together.

Size depends on crowding. Colorado State measures uncrowded kochia at roughly 3 feet tall with a diameter similar to its height, bushy and many-branched, while plants in moderately dense stands grow over 6 feet, single-stemmed and erect. That competition effect likely explains why NC State’s Plant Toolbox lists 1.5 to 2 feet yet notes the plant can reach 7 to 8 feet.

I found no extension key that separates the garden strain from the weedy one in the field, so treat any self-sown plant in a bed as the weedy type. If you are unsure what you are looking at, our guide to 25 common garden weeds covers the look-alikes.

Kochia Through the Year: Seedling to Tumbleweed

Kochia completes its whole life in one season, and the red fall color is the stage just before the plant breaks loose and scatters its seed.

Spring. NDSU records emergence from April through July, with most seedlings appearing in a two- to three-week span very early in spring; Colorado State says germination can begin as early as January. NDSU found the seed usually has no dormancy and that seedlings tolerate frost down to the lower teens (°F).

Summer. The plant grows vegetatively through spring and summer before flowering, according to Colorado State. Its flowers open stigma-first, which favors cross-pollination.

Late summer to fall. The foliage turns color. The Royal Horticultural Society describes bright reddish purple in late summer and autumn, and NC State lists the fall color as red to burgundy.

Fall. A zone of weak tissue near the soil surface lets the mature plant detach whole and roll across the landscape, dropping seed each time it hits something, Colorado State explains. Washington and Oregon both put typical seed output at about 14,600 seeds per plant. NDSU adds that removing the fences and shelterbelts that once stopped tumbling plants made the spread easier.

Does Kochia Come Back Every Year?

Kochia is an annual, so each plant dies at the end of the season, but a patch comes back from seed. NDSU measured 5 percent of seeds still viable after one year in the soil and 1 percent after two; Colorado State gives an average viability of two years. As a rough illustration only, 5 percent of a plant’s 14,600 seeds is still several hundred seeds a year later, which is why one unchecked plant can restock a bed. If no new seed arrives, the seed bank largely runs down within a couple of seasons, but tumbleweeds blown in from a neighboring lot can restart it.

Growing Kochia as an Ornamental (and Why Many Gardeners Skip It)

If you grow summer cypress, treat it as a plant you must actively prevent from seeding. Check your state first: Washington prohibits buying, selling and distributing it, and Oregon prohibits selling and propagating it (see the state table below). California’s agriculture department says kochia has ornamental value but “must be grown in a well-controlled manner to mitigate its spread as a weed,” and NC State’s Plant Toolbox warns that it is problematic and alternatives should be considered.

• Light and soil: The RHS recommends full sun and well-drained soil. NC State prefers moist, well-drained soil high in organic matter. Weedy populations tolerate more: the University of Arizona reports kochia tolerating poor soils, salty soils and drought.
• Planting out: The RHS describes it as a fast-growing, bushy summer annual and advises planting out after the risk of frost.
• Spacing: Sources differ. NC State’s Plant Toolbox lists available planting space as less than 12 inches or 12 inches to 3 feet, with a width of 1 to 1.5 feet, while Colorado State measures uncrowded plants at about 3 feet across. My reading is to allow up to 3 feet per plant if you want the full rounded form; crowded plants shoot up taller and single-stemmed.
• Pruning: The RHS says none is required and plants can be lightly trimmed in summer to tidy the shape.
• Containers: NC State notes that growing it in a container may help manage its spread, since the plant self-seeds easily, especially in zones 8 to 10.
• Stopping seed: Cut or pull plants while they are still green, before the stems dry and break. That is my recommendation, based on the way Colorado State and Washington describe the dry plant detaching and scattering seed.

Kochia vs. Burning Bush (Euonymus alatus): The Name Clash

Kochia and the burning bush shrub are unrelated plants with the same nickname: kochia is a one-season herb, while Euonymus alatus is a woody shrub that lives for years. Both turn red in fall, which is where the confusion starts, and both have restrictions in some states. Always buy and search by Latin name.

Pennsylvania’s agriculture department declared the shrub a noxious weed, and the Minnesota Department of Agriculture lists winged burning bush as Restricted, with propagation and sale prohibited. Our guide to why burning bush is being legislated out of gardens lists the states and the native shrubs that give the same fall color.

Where Kochia Is a Listed Noxious Weed

Washington, Oregon and Arizona list kochia as a noxious weed on their own state lists; Colorado, Montana and New Mexico do not. The table shows what each list says and what it restricts.

Treat three states as the verified minimum, not a census. USDA’s PLANTS profile shows no noxious-weed status for the species, NC State only says “a noxious weed in several states,” and I could not open the full weed lists for Idaho, Nevada, Utah or Wyoming. Your state agriculture department has the current answer, and the rule can differ between selling the plant, planting it and selling seed.

Kochia is not the only ornamental with a split listing. Our pampas grass guide sorts out a similar patchwork of state rules.

Herbicide Resistance: Why Spraying Kochia Is a Gamble

Kochia has evolved resistance to several herbicide modes of action, and Colorado State documents resistance to more than one mode within a single population. NDSU lists confirmed resistance in North Dakota to Group 2 (ALS inhibitors), Group 4 (growth regulators such as 2,4-D and dicamba), Group 5 (including atrazine) and Group 9 (glyphosate), with some plants resistant to two or three groups at once (2 and 4, 2 and 9, or all three). The glyphosate resistance NDSU describes comes from extra copies of the EPSPS gene.

The biology explains why it happens. NDSU points to wide genetic diversity and to pollen that stays viable for up to 12 days, so resistance genes pass to susceptible plants. Resistance to ALS inhibitors appeared in the late 1980s. Colorado State adds that leaf hairs reduce herbicide absorption in the seedling “button stage,” so it advises against spraying then.

Control guidance still includes herbicides. Colorado State’s Grow & Give sheet lists products with fluroxypyr, dicamba or glyphosate as effective on plants 2 to 6 inches tall, and WSU says glyphosate products should be used as spot treatments only. Both sit beside the resistance record above, and the data come from farm fields: I found no extension source measuring resistance in home gardens. For a few plants in a bed, pulling and mowing avoid the question entirely. If you do spray, follow the label and do not rely on one product.

Is Kochia Toxic to Animals?

It can be, mainly to livestock, and the risk depends on growing conditions and plant stage. Montana State University Extension names kochia among weeds that can have high nitrate levels, “especially when growing under adverse conditions.” Nitrate is not itself the poison: rumen microbes normally convert it to nitrite and then ammonia, but when an animal eats too much, nitrite builds up and turns hemoglobin into methemoglobin, which cannot carry oxygen.

MSU lists chronic signs (watery eyes, reduced appetite, weight loss, night blindness, abortion) and acute signs (fast pulse, labored breathing, tremors, weakness, staggering, blue-tinged membranes, death). Acute poisoning can progress within minutes of the first signs, and the only way to save an affected animal is an immediate intravenous dose of methylene blue from a veterinarian, so call one at the first sign.

Texas A&M AgriLife Extension’s rangeland plant page adds oxalates, alkaloids, saponins and sulfate as possible contributors. Oxalates bind calcium, and a rapid drop in blood calcium can cause sudden death; high sulfate may cause polioencephalomalacia. It lists cattle, goats, horses and sheep as affected and says the compounds are thought to be more toxic during drought and when the seeds are mature. Early growth, by contrast, is palatable and has high forage value, and Oregon’s profile notes that certain strains are grown as forage for sheep and cattle.

Two limits matter here. The Colorado State and NDSU kochia pages cover control, not toxicity. And none of the extension pages I read addresses dogs, cats or people, so I will not guess.

How to Get Rid of Kochia in a Garden

Because kochia reproduces by seed only, Colorado State’s one-page guide says the best control is to prevent seed dispersal. In practice:

• Pull seedlings early. Colorado State describes a shallow taproot that is easily pulled or hoed at early stages. Established plants root deeper: NDSU reports roots reaching up to 16 feet in drought. Since emergence runs from spring into July, check beds weekly.
• Disturb the soil as little as you can. WSU warns that careful digging can bring buried seed to the surface, and Colorado State reports that shallow ridge tillage raised kochia densities up to 50-fold in the work it cites, so disturbing the soil can trigger germination.
• Mow before seed. WSU calls mowing to prevent seed production “a very effective means of management.” In one surface-mine reclamation study cited by Colorado State, mowing near flowering cut next year’s seed densities by 98 percent.
• Bag, don’t drag. Dispose of plants that are producing seed, advises Colorado State. A whole dry plant drops seed each time it hits something, so lift a tumbled plant into a bag rather than dragging it.
• Fill the space. A healthy planting competes with weeds, according to WSU. If you wanted fall color, our perennial flowers guide covers plants that return without replanting.

Kochia FAQ

Is kochia invasive?

Yes, in the sense that matters for gardeners: it spreads on its own and is a listed noxious weed in Washington, Oregon and Arizona. USDA classes it as introduced to the lower 48 states, and NC State rates it problematic.

Is kochia toxic to animals?

It can be to livestock. Montana State Extension says kochia can accumulate high nitrate, and Texas A&M AgriLife Extension lists oxalates, sulfate and other compounds as possible contributors. I found no extension guidance for pets or people.

Does kochia come back every year?

Each plant dies in the fall, but seed returns it. NDSU measured 5 percent of seed viable after one year and 1 percent after two, so a patch fades in a couple of seasons only if no new seed arrives.

Is kochia the same as burning bush?

Kochia is called burning bush in USDA and state weed records, but the burning bush shrub most gardeners mean is Euonymus alatus, a different woody plant. Check the Latin name before you buy or remove anything.

Sources

1. USDA Natural Resources Conservation Service. Bassia scoparia (BASC5) profile. PLANTS Database (linked in text)
2. Oregon Department of Agriculture Noxious Weed Control Program. Kochia profile (linked in text)
3. Washington State Noxious Weed Control Board. Kochia
4. Washington Invasive Species Council. Kochia (Bassia scoparia) fact sheet, June 2016
5. Washington State Legislature. WAC 16-752-610, Regulated articles
6. Oregon Secretary of State. OAR 603-052-1200, Quarantine; Noxious Weeds. Cornell Legal Information Institute copy
7. University of Arizona. Kochia. AZ Invasive Plants (linked in text)
8. USDA Agricultural Marketing Service. State Noxious-Weed Seed Requirements Recognized in the Administration of the Federal Seed Act, revised July 2026
9. California Department of Food and Agriculture. Bassia scoparia pest rating and pest rating profile
10. Colorado Department of Agriculture. Noxious Weed Species in Colorado
11. Montana Legislature, Environmental Quality Council. Montana Noxious Weed List, effective June 21, 2019, in the October 2025 committee packet
12. New Mexico Department of Agriculture. Noxious weed memo and list, June 2020
13. North Dakota State University. Kochia (linked in text)
14. Colorado State University, Department of Agricultural Biology. Kochia. Getting Rid of Weeds Through Integrated Pest Management (linked in text)
15. Colorado State University Extension. Kochia one-pager. Grow & Give
16. Montana State University Extension. Nitrate Toxicity of Montana Forages, MontGuide MT200205AG, rev. 03/24 (linked in text)
17. Washington State University Extension. Weeds: Kochia. HortSense (linked in text)
18. NC State Extension. Bassia scoparia (Mexican fireweed). Plant Toolbox (linked in text)
19. Royal Horticultural Society. Kochia scoparia (summer cypress) (linked in text)
20. Texas A&M AgriLife Extension. Kochia. Plants of Texas Rangelands (linked in text)
21. NC State Extension. Euonymus alatus. Plant Toolbox (linked in text)
22. Penn State Extension. Burning Bush (linked in text)
23. Minnesota Department of Agriculture. Winged burning bush (linked in text)