Goosefoot family (Chenopodiaceae)
Description: This introduced or adventive annual plant has a variable size, ranging from 1-6' tall. Large plants branch frequently and are wider at the base. Young stems are pubescent, but older stems near the base are usually glabrous. The alternate leaves are up to 2½" long and ¼" across. They are linear, narrowly lanceolate, or narrowly oblanceolate, and sessile against the stems. Their margins are smooth and ciliate. Clusters of 2-6 flowers develop near the axils of the leaves in young stems. These clusters of flowers slowly lengthen to become short hairy spikes about ½–2" long. These spikes have leafy bracts that are about ½" long and linear in shape. The silky hairs of the spikes can be as long as the bracts. Each flower is about 4-5 mm. across, consisting of a divided style, 5 stamens with large yellow anthers, 5 green sepals, and no petals. Each sepal is shaped like a blunt triangle and becomes winged along its outer surface as the flower matures into a fruit. The flowers are greenish yellow in overall appearance – were it not for their abundance along the stems, they would be rather inconspicuous. The blooming period occurs from mid-summer to early fall and lasts about 1-2 months. Each flower is replaced by a somewhat flattened capsule that contains a single seed. This capsule is enclosed by the sepals until it is ready to release the seed. The flattened seed is well-rounded on one end and tapers to a point on the other, resembling a teardrop. It is more or less brown and has a rough surface. During the fall or winter, Kochia often breaks off at the base of the central stem and becomes a tumbleweed that is driven about by the wind, in this manner distributing its seeds. The root system consists of a taproot. This plant spreads by reseeding itself, and sometimes forms colonies.
Cultivation: The preference is full sun, dry conditions, and a barren soil that is sandy or gravelly. Soil with a high pH is readily tolerated.
Range & Habitat: Kochia occurs occasionally in central and northern Illinois, but it is less common or absent in southern Illinois (see Distribution Map). However, Kochia is still spreading into many areas of the state where it was not previously observed. Habitats include pastures, roadsides, areas along railroads, landfills and urban dumps, and sterile waste areas. In Illinois, Kochia is primarily a weed along railroads. It prefers disturbed sites and has not invaded natural habitats to any significant degree, although it could potentially invade gravel and sand prairies in the future. Kochia can appear in recently burned over areas because of its tumbleweed characteristic. It is native to Asia.
Faunal Associations: The flowers are wind-pollinated and do not attract many insects. The fuzzy orange caterpillars of Spilosoma virginica (Virginia Tiger Moth) feed on the foliage (personal observation). This moth species is highly polyphagous and attacks a variety of weedy plants in the Goosefoot family. Several species of grasshoppers also feed on the foliage of Kochia, including Dissosteira carolina (Carolina Grasshopper), Melanoplus bivittatus (Two-striped Grasshopper), Melanoplus differentialis (Differential Grasshopper), Melanoplus femurrubrum (Red-legged Grasshopper), Phoetaliotes nebrascensis (Large-headed Grasshopper), Spharagemon collare (Mottled Sand Grasshopper), Melanoplus lakinus (Lakin Grasshopper), and Brachystola magna (Plains Lubber Grasshopper); see Wyoming Agr. Exp. Station (1994), Brust et al. (2008), and Joern (1985). The last two species of grasshopper occur west of Illinois. During the early stages of growth, Kochia is highly palatable to all classes of livestock, and it is also browsed by deer. However, if the foliage of mature plants is eaten in large quantities, it can cause toxic reactions in livestock, including photosensitization and neurological problems (Casey, 2009). Another mammal, the Prairie Vole, also feeds on the foliage and possibly other parts of Kochia (Fleharty & Olson, 1969).
Photographic Location: Along a railroad in Champaign, Illinois.
Comments: What distinguishes Kochia from similar species in the Goosefoot family, such as Salsola kali (Russian Thistle), is the lack of significant thorns or prickles in the foliage. There is a cultivated form of Kochia that is occasionally grown in gardens as an ornamental plant. This cultivated form is quite different in appearance, having foliage that is light green and softer in texture than wild Kochia. The cultivated form occasionally reseeds itself and escapes, but it rarely persists in either waste areas or the wild. Sometimes Kochia is called 'Burning Bush' because the foliage turns red during the autumn. Where this plant is abundant, it can cause allergic reactions in people during the late summer or autumn because of the airborne pollen.