Davey Tree Flipbooks

48 WILD MUSTARD (Sinapis arvensis) PLANT DESCRIPTION Wild mustard, or charlock, is a broadleaf summer or winter annual weed that can be seen from spring to fall as an upright 2–4 foot tall plant with bunches of yellow flowers at the end of the upper branches. Wild mustard can also be found as a seedling from spring to late summer. Since wild mustard seeds can germinate twice in one growing season, mature plants with flowers can be seen from spring to fall. LEAF: The leaves of wild mustard vary in shape and number of lobes. Lobeless leaves are egg shaped. Leaves have one or two sets of lobes at the base. Leaves are more dense in the lower portion of the plant, but as wild mustard matures the canopy becomes sparse. STEM: Stems are dark green and glossy, but are sparsely covered in short white hairs. As wild mustard prepares to flower, branching occurs towards the top of the plant. FLOWER: Small yellow flowers with four petals bloom along the branches, which eventually produce seed pods. SEED: Wild mustard's seeds form in pods that look like miniature green bean pods. REPRODUCTION: Seeds function as the primary means of reproduction. Most seeds drop below the parent plant. A mature wild mustard plant is capable of producing thousands of seeds that can remain viable in the soil for up to 20 years. WHY IT IS NOXIOUS: Wild mustard is a significant agriculture weed with a root system that competes with crops for resources. Seeds are toxic to humans and livestock if consumed. SEASONAL IDENTIFICATION WHEN TO FIND: Wild mustard can be seen all season long when it is flowering. Flowering has been observed in central Ohio from late spring to midfall. SPRING IDENTIFICATION = DIFFICULT As a young plant or seedling, wild mustard is found growing low to the ground and can only be identified by the leaves. Egg-shaped or oval leaves tend to have one or two lobes at the base of the leaf near the stem, and stiff hairs on the underside. SUMMER IDENTIFICATION = MODERATE TO DIFFICULT Look for yellow flowers with four petals, 1–2 inches wide, and green seed pods. Wild mustard does not exceed 4 feet in height. There are many look-alikes. FALL IDENTIFICATION = DIFFICULT The plant can be identified by its seed pods. The stalk of the pod is short and extends outward and upward from the stem. Some wild mustard plants turn bright red in fall. WINTER IDENTIFICATION = DIFFICULT Wild mustard may persist into winter during warm years, but it usually withers and decomposes before spring. SIMILAR-LOOKING SPECIES BROWN MUSTARD (Brassica juncea) is a similar-looking mustard. It often has a waxy coating on the stem. The stalk of seed pod is very small (10–15mm long). BLACK MUSTARD (Brassica nigra) is a similar-looking mustard. The leaves, flowers, and stems look very similar, but black mustard is usually over 4 feet tall. YELLOW ROCKET (Barbarea vulgaris) flowers are similar to wild mustard and can be widespread in spring. These flowers appear early in the growing season, long before wild mustard flowers. Leaves have deep, multiple lobes. FIELD MUSTARD (Brassica rapa) is a similar-looking mustard. It contains leaves that wrap around the stem. Leaves have short, stiff hairs on their margins and veins. LOW HIGH ohio distribution roadside distribution growth seeds ability to dominate difficulty of control WHERE TO FIND: Wild mustard can be found in farm fields across central Ohio. Wild mustard can be found invading the right-of-way from farm fields and may be found in mowed turf or ditches. Wild mustard prefers well-drained soil and full sun. CONTROL METHODS: MECHANICAL: Mow in spring and late summer to reduce seed production. Hand pull to control individual plants. CHEMICAL: Make directed applications to young wild mustard plants with selective herbicides in spring or fall. CULTURAL: Plant tall fescue in early fall allowing it to grow tall in spring. RECOMMENDATION SUMMARY: Wild mustard can be a summer or winter annual. As a summer annual, the seeds germinate in the spring and flower in the summer. When acting as a winter annual, wild mustard seeds germinate in late summer or fall and produce seeds before winter. When wild mustard germinates in spring, the colonies are usually larger and produce more seeds than the germinated seeds in fall. For best control results, make directed herbicide applications in spring before flowers bloom. Only make fall applications if winter annual colonies present themselves. Mowing will not provide control of a wild mustard population but can reduce seed production. Plant tall fescue in early fall and allow to grow tall in spring to provide competition and reduce spring seed germination. Failure to control wild mustard may allow further spread of this weed from roadways to neighboring agriculture lands. winter annual summer annual OR RIVM LEVEL OF CONCERN

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