See “ Eating Weeds: Why Not? ” 10 Ways to Prevent Weeds Before They Become a Problem Many weeds stabilize the soil and add organic matter. Some are edible to humans and provide habitat and food for wildlife, too. Keep in mind: Of approximately 250,000 species of plants worldwide, only about 3% behave as weeds that we don’t want in cultivated areas. When in a foreign environment, these invaders often lack natural enemies to curtail their growth, which allows them to overrun native plants and ecosystems.” Many invasive weeds are also classified as noxious. Invasive Weed: “Weeds that establish, persist and spread widely in natural ecosystems outside the plant’s native range.
See a list of noxious weeds by state here. Once a weed is classified as noxious authorities can implement quarantines and take other actions to contain or destroy the weed and limit its spread.” For example, Field Bindweed is considered a noxious weed. Noxious Weed: “Any plant designated by federal, state or local government officials as injurious to public health, agriculture, recreate, wildlife or property.Weed: “A plant that causes economic losses or ecological damages, creates health problems for humans or animals or is undesirable where is it growing.” Think crabgrass, giant foxtail or common lambsquarters, for example.Here are definitions from the Weed Science Society of America: They are purplish brown, brown, or black and either smooth or have tiny star-shaped hairs.There are different types of weeds. Seeds range from kidney shaped to almost triangular, have a notch, are flattened, and about 1/12 to 1/8 of an inch (2–3 mm) in length. The segments remain intact at maturity and each segment releases 1-3 seeds through a vertical slit on the outer face of the capsule. The fruit is a capsule (similar to a pod) that consists of a cuplike ring formed by 12 to 15 woody segments and is roughly 1 inch (2.5 cm) in diameter. They are 2/5 to 1 inch (1–2.5 cm) in diameter, have five yellow petals that are fused at the base, are stalked, and found singly or in clusters where the leaf stalk meets the stem. Flowersįlowers bloom from July through August. Plants have a distinct odor when crushed. Leaves are densely covered with short, soft, simple hairs and star-shaped hairs, have long stalks that are about 4 to 8 inches (10–20 cm) long, and are alternate to one another along the stem. Stems are coarse and grow to 5 feet (1.5 m) tall or more. Velvetleaf stands erect and has large, velvety heart-shaped leaves with pointy tips. The next leaves are about 4/5 to 1-3/5 inches (2–4 cm) long and as wide and resemble leaves of the mature plant. The first true leaf is heart shaped with a rounded tip, and is slightly larger than the cotyledons. Cotyledon stalks are long and covered densely with two kinds of hair: short, simple hairs and star-shaped hairs. The cotyledons are about 1/3 to 1/2 of an inch (7–12 mm) long and about as wide, and often have slightly indented tips. Both are covered with soft, tiny, simple hairs. SeedlingĬotyledons (seed leaves) usually differ slightly in shape-one roundish and the other slightly heart shaped. Orchards, vineyards, crop fields-especially agronomic and nursery crops, gardens, roadsides, and other disturbed areas. If infestations are allowed to persist and produce seed, this weed can be troublesome. Seeds can remain viable in soil for 50 years. It also harbors several diseases and pests of corn, cotton, soybeans, and other crops. Because of velvetleaf’s tall growth, it can severely reduce light penetration to crop plants. Velvetleaf can also grow in urban environments and other irrigated disturbed areas.
It is also found in irrigated areas of the desert regions. In California, it is found in the southwestern region and the Central Valley, especially in the Sacramento Valley to an elevation of 330 feet (100 m).
It was introduced to North America from southern Asia in the mid-1700s as a potential fiber crop. Velvetleaf, a summer annual broadleaf plant, is a problematic weed for many crops in the United States, particularly where cotton, corn, or soybeans are major crops.