Kochia

Bassia scoparia

Synonyms - Kochia scoparia, Bassia sieversiana, Chenopodium scoparia, Kochia alata, Kochia parodii, Kochia sieversiana, Kochia trichophila, Kochia virgata.

Family: Chenopodiaceae

Names:

Bassia commemorates Ferdinando Bassi an Italian naturalist who died in 1774.
Scoparia is from the Latin scoparia meaning 'sweeper' referring to the tree's broom-like shape
Scoparia is from the Latin word scopae, meaning thin twigs or shoots referring to the maze of branches making up the tumbleweed like structure and the Latin scoparia means sweeper as these thin twigged plants were often used as brooms.
Kochia because it used to be in the Kochia genus and commemorates W. D. J. Koch, a German botanist who died in 1849.

Other Names:

Belvedere
Belvedere Cypress
Broom-cypress
Burning Bush
Fireball
Fireweed
Mexican Burning Bush
Mexican Fireweed
Mock Cypress
Morenita
Poor Man's Alfalfa
Red Belvedere
Summer Cypress

Summary:

Kochia is an erect, summer growing, bushy, salt tolerant, pyramid-shaped, tumbleweed that grows up to 2 metres tall. It turns red purple in autumn and the plant breaks off at the base and tumbles in the wind to distribute seed. It has slender, hairy leaves and inconspicuous flowers and fruit.

Description:

Cotyledons:

Two. 3-6 mm long by 1-2 mm wide. Dark green on top and often pinkish underneath. Linear to narrowly lanceolate. Hairless.

First leaves:

3-6 mm long by 1-2 mm wide. Grey-green. Linear to narrowly lanceolate, covered in long, soft white hairs and form a small rosette.

Leaves:

Alternate. Initially green and turning reddish purple in autumn.
Forms a basal rosette when it isn't competing with neighbours.
Stipules -
Petiole -
Blade - Lance shaped to parallel sided. 5-60 mm long by 1-10 mm wide, becoming smaller near the tips of the branches. The edges and underside are usually hairy and the upper surface maybe nearly hairless. Margins smooth. 3-5 veined from the base in the lower portion of the plant.

Stems:

Somewhat hairy. Many branched. The stems break off at the base when the plants dies.

Flower head:

Inconspicuous, stalkless (sessile) groups of 2-6 flowers in the leaf axils.

Flowers:

Small, 3 mm wide and green. Mostly bisexual.
Ovary - 2 styles
Calyx - Radial, 5 lobed, 1-2 mm wide. Lobes are glabrous to ciliate or sparsely hairy, usually with knoblike tubercles or sometimes short horizontal wings when in fruit. Tubercle or wings are less than 1 mm wide or long.
Petals - None.
Stamens - 15. Some flowers may have no stamens.
Anthers -

Fruit:

Single seeded nut (achene or utricle) often enclosed by the calyx. 5 thickened or knoblike lobes (tubercles) or short horizontal wings.

Seeds:

Egg shaped, black to dark reddish brown. 1-2 mm long by 1-1.5 mm wide. Surface is dull and somewhat granular. Grooved on each face. Contains an annular embryo.

Roots:

Taproot with a few to several branches and fibrous lateral roots. Up to 2000 mm deep and 3000 mm horizontally.

Key Characters:

Plants hemispherical to pyramid shaped and turn reddish in autumn.
Alternate, flat, lanceolate and hairy leaves.
Radial fruits with tubercles or small wings.

Biology:

Life cycle:

Annual.

Physiology:

C4 plant.
Tolerates saline and alkaline soils.
Contains saponins.
Seedlings are tolerant of frost.
Drought tolerant.

Reproduction:

By seed.

Flowering times:

Summer to autumn.

Seed Biology and Germination:

Seed is short lived with little dormancy. In the eradication program, occasional seedlings were found up to 3 years after seed set was stopped.
Shallow burial usually reduces seedling emergence.
Seed on the surface usually survives for about 1-2 years and buried seed lasts longer.

Vegetative Propagules:

None.

Hybrids:

Garden cultivars have been produced e.g. variety trichophila

Allelopathy:

It is allelopathic.

Population Dynamics and Dispersal:

Reproduces by seed that is dispersed as the plant forms a tumbleweed and drops seed as it rolls across the landscape.

Origin and History:

Europe and Asia.
Introduced to Western Australia in 1994xxx1990 in Western Weeds as a salt land forage plant. Then eradicated by John Moore and the APB over the next few years.

Distribution:

WA - now eradicated.
Canada, USA.

Courtesy Australia's Virtual Herbarium

Courtesy DPAW

Habitats:

Wetlands.

Climate:

Temperate.

Soil:

Tolerates a wide range of soils including alkaline and saline soils.

Plant Associations:

Salt land species such as Atriplex (Saltbush) and Maireana (Bluebush) species.

Significance:

Beneficial:

Ornamental.
Promoted as a forage crop and readily grazed but animals grazed on it do not perform well.

Detrimental:

Weed of roadsides, railways, disturbed areas, ditch edges and seasonal wetlands.
Serious weed of cropping that reduces yields substantially and interferes with harvesting by blocking machines and contaminating the grain with green material.
Alternate host for Beet Yellows Virus and Tobacco Mosaic Virus.

Toxicity:

Contains low level toxins that reduce animal performance rather than killing them. It contains saponins, nitrates and oxalates and a thiaminase degrading compound.
Toxicosis has been reported overseas.
Generally toxicity only occurs when it is more than half of the diet.

Symptoms:

Poor weight gain. Liver dysfunction, photosensitivity and neurological symptoms.

Treatment:

Remove animals from the infestation.

Legislation:

Declared plant or noxious weed in all states of Australia.
Noxious weed of several states in the USA.

Management and Control:

Early summer cultivation or heavy grazing will control seedlings. Atrazine plus 2,4-D ester provides good control in fallows. Late applications of chlorsulfuron provides good control in winter cereals on susceptible populations. Glyphosate at rates greater than 1 kg a.i. provides good control in non selective situations. Plants usually reshoot after mowing or late grazing.
Shallow tillage provides good control.

Thresholds:

1-2 plants per square metre cause significant yield losses in cereals.

Eradication strategies:

Apply 1 kg atrazine900 plus 1 L 2,4-D ester800 per hectare in early summer and repeat in late summer if necessary.

Herbicide resistance:

Populations resistant to sulfonylurea (group B) herbicides.

Biological Control:

Related plants:

There are about 40 species of native Kochia or Blue Bushes in Australia. Most of these have been reassigned to the Maireana or Bassia species group.
Bassia scoparia is often misidentified.
Bassia species tend to have fleshier leaves and hooked spines on the sepals whereas Kochia has no spines.

Plants of similar appearance:

Distinguished from most other Chenopodium species by having flat lanceolate leaves, hairy foliage and radial fruits with tubercles.
Fat Hen (Chenopodium album)
Nettle-leaved Goosefoot (Chenopodium murale)

References:

Bodkin, F. (1986). Encyclopaedia Botanica. (Angus and Robertson, Australia).

Everist, S.L. (1974). Poisonous Plants of Australia. (Angus and Robertson, Sydney).

Hussey, B.M.J., Keighery, G.J., Cousens, R.D., Dodd, J. and Lloyd, S.G. (1997). Western Weeds. A guide to the weeds of Western Australia. (Plant Protection Society of Western Australia, Perth, Western Australia). P136.

Paczkowska, G. and Chapman, A. (2000). The Western Australia flora: a descriptive catalogue. (Wildflower Society of Western Australia (Inc), the Western Australian Herbarium, CALM and the Botanic Gardens & Parks Authority). P201.

Randall, J.M. and Marinelli, J. (1996) Invasive Plants. (Brooklyn Botanic Gardens Inc. Brooklyn). P. Photo.

Royer, France and Dickinson, Richard. (1999). Weeds of Canada and the Northern United States. (University of Alberta Press, Edmonton, Alberta, Canada). P158-159. Photos.

DiTomaso, Joseph M., Healy Evelyn A. (2007). Weeds of California and Other Western States. Publication 3488. (University of California, Agriculture and Natural Resources, Oakland, California). P594-599. Photos.

Acknowledgments:
Collated by HerbiGuide. Phone 08 98444064 or www.herbiguide.com.au for more information.