Davey Tree Flipbooks

24 KOCHIA (Kochia scoparia) PLANT DESCRIPTION Kochia, or summer cypress, is a broadleaf summer annual weed that can be seen from summer to fall as a pyramidal-shaped bush that is 1–5 feet tall with many spreading branches. Kochia can also be seen as a seedling in late spring. Kochia is easily identified by its pyramidal form and dense canopy of narrow leaves. LEAF: Kochia leaf blades attach directly to the stem, are small, slender, and are covered in hairs. Leaf veins run parallel to the leaf margins. Leaf hairs are inconspicuous when young. As the plant matures, the leaves become smaller and the hairs become denser and more visible. STEM: The stems and branches display smooth vertical stripes that range from light to dark green, but can also be vibrant tints of red. FLOWER: By late summer, small inconspicuous flowers bloom along the branches, filling in the spaces between the slender leaves. The five petaled flowers are very small and range in color from yellow to variations of red. SEED: After flowering, tiny, irregular-shaped black seeds form within the flowers and are usually held until disturbed by animals, equipment, or hand pulling. REPRODUCTION: Seeds are the primary means of reproduction with most seeds dropping below the parent plant. Mature kochia can produce thousands of seeds that may be viable in the soil for one to two years. Seeds germinate in late summer after most Ohio summer annuals. WHY IT IS NOXIOUS: Kochia can overtake guardrails at the edge of the road creating visibility and maintenance concerns. Kochia also has demonstrated herbicide resistance. SEASONAL IDENTIFICATION WHEN TO FIND: Kochia is most noticeable in summer after branches develop a distinct pyramidal form with dense, narrow leaves. It is also easy to identify when the plant color changes in late summer. SPRING IDENTIFICATION = MODERATE Kochia seedlings prefer disturbed or dry sites. The small, slender leaves attach directly to the stem and are covered in hairs. Leaf veins are parallel to the leaf edge. SUMMER IDENTIFICATION = EASY Strong lateral branching creates a pyramidal form with striped stems ranging from green to red in color. The yellow flowers are produced along the branches. The leaf hairs become long and dense, which makes the branch feel soft. FALL IDENTIFICATION = EASY As kochia matures and completes its life cycle, it turns from green to bright red to tan. Not all plants turn red but all eventually turn tan after dying. Large colonies should be easy to locate until winter. WINTER IDENTIFICATION = MODERATE Dead kochia stems may stay standing until heavy snowfall but are not easy to identify unless in large colonies. SIMILAR-LOOKING SPECIES RUSSIAN THISTLE (Salsola kali var. tenuifolia) grows in a similar bushy form but is more round. The leaves are narrow and needle like with spine tips that are sharp to the touch. MUGWORT (Artemisia vulgaris) looks similar from a distance in form and color. The leaves are highly divided with lobed margins. The leaves can be variable in appearance throughout the plant. LOW HIGH ohio distribution roadside distribution growth seeds ability to dominate difficulty of control WHERE TO FIND: Kochia is becoming more and more common in Ohio at the edge of the road and under rails. Single plants may be found but dense colonies are easy to spot. Kochia prefers full sun and well-drained, disturbed soil. Kochia is most often found in areas that have been sprayed in the past for bare ground. CONTROL METHODS: MECHANICAL: Mow to maintain visibility and to reduce seed production. Hand pull to remove individual plants. Grade road edge to control seedlings. CHEMICAL: Broadcast pre-emergent herbicide to soils of infested areas in early summer before seeds germinate. Make broadcast applications to kochia with selective herbicides and added surfactant in summer before leaf hairs become dense. Kochia can be resistant to herbicides. CULTURAL: Install paving when appropriate near roadway. RECOMMENDATION SUMMARY: Kochia can be an aggressive summer annual weed that can take over guardrails and disturbed sites. For best control results, perform herbicide applications in summer before the leaf hairs become dense and prevent herbicide from reaching the small leaves. Always add surfactant when making foliar applications to increase the herbicide's ability to penetrate leaf hairs and reach the leaf surface. Kochia has shown an ability to develop resistance to many commonly used herbicides including ALS-inhibiting herbicides and glyphosate. Always monitor herbicide applications for effectiveness. If a second application is required for control, use alternate herbicides with different modes of action. If a large colony produces seed, prevent future germination by making pre-emergent herbicide applications to soil in early summer before seeds germinate. Mow or cut to maintain visibility and reduce seed production. Hand pull individual plants. Grading the road edge can also control young kochia plants growing at the edge of the road. Grading can be used to control existing population of seedlings but is not suggested as a preventative measure. Failure to control kochia will allow this aggressive weed to produce thousands of seeds, increasing the distribution along the road edge and creating maintenance and visibility concerns. summer annual RIVM LEVEL OF CONCERN

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