Quick Facts

Quick facts

• Originally from eastern Europe and western Asia, Kochia (Bassia scoparia) is a large annual herb, originally planted for fodder and to help rehabilitate saline soils, quickly became weedy.
• Kochia's tumbleweed behaviour, coupled with its annual life-cycle allows it to spread seed over long distances in short times.
• Preventing the spread of Kochia will protect the cereal crops and pastures of much of temperate, semi-arid and sub-humid Australia.
• A concerted effort to eradicate Kochia from Western Australia was highly successful with the species being eradicated from over 2000 ha of infested land.
• Populations of Kochia should be reported to your local council, or state or territory weed management agency.
• Kochia is an extremely hardy plant that can tolerate both drought conditions and saline soils.

What Does It Look Like?

What is it?

Kochia (Bassia scoparia) is a fast growing annual herb that grows to 1.5 m high. As the plant ages the colour of its stems, leaves and flowers changes from green to pale yellow, pink and dull brown (Department of Agriculture and Food 2007). It has an erect main stem with many upward-curving side stems (CRC 2003) and forms a pyramidal to rounded bush. The leaves are arranged alternate along the stem, have no petiole (leaf stalk), green then change to yellow, red and then brown as the plant ages, up to 50 mm long and up to 8 mm wide, with 3 to 5 veins running lengthwise on the underside, often hairy on the edges.

The flowers are borne on the upper part of the branches near the tip, are the same colour as the leaves, occur singly or in pairs, in short hairy spikes (up to 10 mm long).

The seeds of Kochia are dull-brown, 1.5 mm wide and are contained in small star-shaped fruits. When the seed is ripe the plants die, break off at the base and are blown around by the wind in a tumbleweed fashion, dispersing seed as they move (CRC 2003).

The species Bassia scoparia is extremely variable. Where it is native, several geographical races occur and these are sometimes treated as different subspecies or forms (e.g. see CRC 2003; Mosyakin 2003), but these are not recognised as distinct in Australia.

Recognition: This species can normally be recognised by the combination of the following characters; fast growing annual rounded herb that grows to 1.5 m high; all part change colour over time from green to pale yellow, pink and dull brown; flowers on the upper part of the branches near the tip, and are the same colour as the leaves; seeds are dull-brown, 1.5 mm wide and are contained in small star-shaped fruits; plants die break off at the base and are blown across landscape like tumble weeds.

For further information and assistance with identification of Kochia contact the herbarium in your state or territory.

Flower colour

Green then change to yellow, then red and then brown

Growth form (weed type/habit)

Herb

Where it currently grows? Preferred habitat

Kochia is native to arid and desert regions of Eurasia (Mosyakin 2003). It is an annual weed of crops and pastures throughout the world, especially in regions with warm climates (Dodd 2004). Kochia grows well in conditions similar to those required by cereal crops in southern Australia; that is, climates with hot, sunny summers (CRC 2003). It is extremely drought tolerant and, in the United States, grows in areas that receive as little as 150 mm of rainfall per annum (Esser 1995; CRC 2003). It invades disturbed sites, crops, pastures, flood plains, riparian habitats and rangelands (Esser 1995; CRC 2003). It tolerates saline soils and can flourish even when irrigated with water that is one-third the salinity of seawater (CRC 2003). It prefers open unshaded areas (Esser 1995). Much of central and southern Australia is climatically suitable for Kochia (CRC 2003). The ability of Kochia to prosper on degraded and saline sites has lead to it being used as a revegetation and fodder species in Australia (CRC 2003) and North America (Esser 1995).

Are there similar species?

Kochia resembles Bassia hyssopifolia, the only other species of Bassia that occurs in Australia. It may also be mistaken for Galvanised Burr (Sclerolaena birchii), Fat Hen (Chenopodium album) and Roly Poly (Salsola australis) [as Salsola kali] (Navie 2006).

Why Is It A Weed?

What are its impacts?

Kochia (Bassia scoparia) is on the Alert List for Environmental Weeds, a list of 28 non-native plants that threaten biodiversity and cause other environmental damage. Kochia is well adapted to out-compete crop, pasture and native plants and it also impacts human health causing allergies. Kochia spreads rapidly producing chemicals from its roots that inhibit the growth of nearby plants (allelopathic), i.e. it gives itself a competitive advantage by producing chemicals that reduce the growth rate and germination of other nearby desirable plant species (CRC 2003; Esser 1995). Its tumbleweed behaviour and annual lifecycle allows it to spread seed over long distances in short times. Its fast growth rate results in a large plant that competes for both light and nutrients

Agriculture: It competes with pastures reducing productivity, contaminates and reduces crop production (including cereal crops) and hosts crop disease (DPI NSW 2019). Kochia can infest many different crops as well as pastures, fire-breaks, fence-lines, roadsides and railway lines. (DPIRD WA 2020). Livestock readily graze Kochia, and it is considered a good forage plant in arid and semi-arid parts of the United States of America. However, it is toxic if overgrazed (Esser 1995). High levels of oxalate, nitrate and alkaloids are contained in the plant, and accumulations of these compounds can lead to toxicity (CRC 2003; Department of Agriculture and Food 2007). Kochia, eaten in large quantities has caused deaths in cattle, sheep and horses. The shoots contain chemicals (oxalates, nitrates and alkaloids) that can poison animals. Poisoning symptoms can include, dehydration, weight loss, weak muscles, runny eyes, sensitivity to sunlight (DPI NSW 2019).

Native ecosystems: Can alters fire regimes by increasing fuel loads in  saline areas. Not widely recorded as a weed of native areas, However, it is able to grow and colonise saline areas and has the potential to seriously degrade Australia's ecosystems (CRC 2003). Kochia (Bassia scoparia) is on the Alert List for Environmental Weeds, a list of 28 invasive plants that have the potential to threaten biodiversity and cause other environmental damage in Australia. It was included on this list because of its rapid spread from deliberate plantings in Western Australia, and because of its history of invasiveness overseas (e.g. it is one of the fastest spreading of all invasive plants in the USA). It can also alter fire regimes in natural ecosystems and form dense infestations that reduce the abundance of native plants.

How does it spread?

Kochia reproduces by seed. Up to 50 000 seeds may be produced by a single plant during its one-year lifespan, although typically about 14 600 seeds are produced (Esser 1995). The main mechanism for the dispersal of seeds is by the tumbleweed nature that the plant exhibits. After the seeds are mature, the plants die off, break at the base and get blown around by the wind, spreading seed as they go (Esser 1995; CRC 2003). Water currents may also disperse seed (Esser 1995). Seeds of Kochia have a very short viability, and if the seeds don't germinate, they usually decay within one year (Esser 1995).

What is its history in Australia?

Kochia was introduced into Western Australia deliberately in 1990 as a forage plant and for re-vegetation of land with high salinity.Very soon after its introduction, it began to spread from the original sites of introduction and was recognised as a weed. An eradication program was initiated in early 1992 and no plants have been observed in Western Australia since March 2000. A total of 81 infestations ranging in size from less than 10 ha through to more than 1000 ha were eradicated (Dodd 2004). Several small infestations of Kochia have also been discovered in Tasmania, where it appeared as a weed in carrot crops, from seed imported from North America (CRC 2003). The first occurrence in Tasmania was in 1992 and no plants have been reported since 1998.

How To Manage It?

Best practice management

A variety of control methods have been successfully used against Kochia (Bassia scoparia) in Australia. Methods used in the eradication of Kochia from Western Australia include the application of herbicide, grazing, burning of large seeding plants to destroy formed seed, and mechanical removal (Dodd 2004). These methods proved to be very successful with most infestations being eradicated within 2 years of starting the control (Dodd 2004). In some instances in North America, Kochia has become resistant to sulfonurea and triazine herbicides (CRC 2003).

Chemical control:  Herbicides were delivered from the ground and aerially for larger infestations (CRC 2003). See DPIRD (2020) & DPI NSW (2019) for list of chemical controls and the rates. Please see the Australian Pesticides and Veterinary Medicines Authority for chemical information http://www.apvma.gov.au 

Non-chemical control: High densities of sheep were used to provide extreme grazing pressure that caused defoliation of large plants and destruction of seedlings. Grubbing, the physical removal of plants from the ground, was also conducted where appropriate. Flaming, where plants are burnt by a flame thrower or similar, was used on mature, seeding plants to kill the seeds (CRC 2003). in Tasmania in 1995,1997 and 1998, when seeds were discovered as a contaminant of imported carrot seed, hand pulling was used to remove all plants, which numbered less than 50 in each of the infestations. Although some plants set seed at some sites, no seedlings were found, possibly because of the herbicides used to control other weeds (CRC 2003).

Do not try to control Kochia without expert assistance. Control effort that is poorly performed or not followed up can actually help spread the weed and worsen the problem (CRC 2003). For a summary of eradicating Kochia in Western Australia, see; Dodd (2004); Dodd and Randall ( 2002).

Does it have a biological control agent?

NO

When does it grow? (lifecycle/growth calendar)

Kochia is a summer growing annual. Most seed germinates in spring and early summer but if suitable rainfall occurs in late summer, germination may continue throughout autumn. The plants have a fast growth rate. Flowering occurs mainly between late summer and the end of autumn, although seedlings that germinate early or late in the season can flower at any time of the year. Plants die off after the seeds are formed. This usually occurs during autumn but, as with flowering, can occur at any time of the year depending upon the time of the germination. Plants usually complete their life cycle in six to seven months (CRC 2003).

Where Is It Found?

Which states and territories is it found?

NSW, QLD, SA, TAS, WA

What areas within states and territories is it found?

Prior to Kochia being eradicated from Western Australia, it was introduced widely and became a widespread weed, particularly in Western Australia's Southwest region including in the Avon wheatbelt, Esperance Plains, Geraldton Sandplains and Mallee sub-regions (Western Australian Herbarium 1998-). A total of 81 infestations, ranging in size from less than 10 ha through to more than 1000 ha, were recorded in Western Australia (Dodd 2004). In Tasmania, infestations have been recorded in carrot crops near Deloraine and Devonport in the state's north. Kochia is now regarded as eradicated in Western Australia and Tasmania (Dodd 2004; CRC 2003). Kochia is also recorded in South Australia, Victoria, New South Wales and Queensland (AVH 2007 – as both Kochia scoparia and Bassia scoparia).

Kochia is naturalised throughout the United States especially in the Southwest and Great Plains regions where it has become a serious weed in pastures and rangelands (Esser 1995; Mosyakin 2003). It is also naturalised in Canada (Esser 1995), Africa (African Plants Database), South America, parts of temperate Asia and most of Europe (CRC 2003).

Where does it originate?

Kochia is native to eastern Europe and western Asia (Mosyakin 2003). In Europe, it is thought to be native only in southern and eastern Russia, but it is widely cultivated elsewhere, and is naturalised in the central, southern and eastern regions (Ball & Akeroyd 1993).

National And State Weed Listings

Is it a Weed of National Significance (WONS)?

NO

Where is it a declared weed?

NSW, SA, TAS, WA

Government weed strategies and lists – Weeds Australia

Is it on the National Alert List for Environmental Weeds?

YES

Government weed strategies and lists – Weeds Australia

Is it on the Agricultural Sleeper List?

NO

Government weed strategies and lists – Weeds Australia

Names And Taxonomy

Main scientific name

Bassia scoparia subsp. densiflora

Other scientific names (synonyms)?

• Chenopodium scoparia L.
• Kochia scoparia (L.) Schrad

Does it have other known common name(s)?

Summer Cypress, Tumbleweed, Burning Bush, Mexican Burningbush, Mexican Fireweed, Fireweed, Mexican Firebush, Firebush, Common Kochia, Belvedere, Red Belvedere, Belvedere Cypress, Mock Cypress, Broom-cypress, Fireball.