Where Did All of These Weeds Come From?
Have you ever wondered how all of the troublesome weed species you deal with came to be? Of course, many weeds are native to North America, but many weeds have entered North America accidentally, by neglect of seed purity and imports from many years and decades ago. Some weeds were purposely brought to the “New World” for early settlers benefits and sustainability.
Here’s some background on a few common North American weeds:
Canada Thistle and Musk Thistle
Canada Thistle was introduced in the 1700s, and Musk Thistle 200 years later, from Europe, Asia and North Africa areas. Both are invasive and noxious weeds that require control. Some birds will feed on the thistle seeds. In Europe and Asia, the flowers are dried and used to curdle milk, and the pith from roots and stems are boiled and eaten.
Dandelions are currently one of the most common lawn weeds in North America. It’s French meaning is, “tooth of the lion.” Dandelion is another weed whose origin is Europe and Asia. European settlers brought dandelion seed and seedlings to America in the mid-1600s. They cultivated the dandelions in their gardens as a food source and for medicinal uses. Most mammals ingest the leaves of dandelion, which has a moderate forage value. Birds consume the seeds, and the flowers supply nectar to honeybees. Settlers ate the dandelion leaves as spring greens. Dandelion roots were used to treat several ailments including heartburn or as a mild laxative, and tea and wine were produced from the flowers.
Henbit originates in Asia and North Africa, arriving in North America in the 1700s from ship ballast and livestock feed. Although a troublesome weed in row crop production, it has some beneficial characteristics. Henbit is an edible herb that can be consumed raw or cooked, even used for tea. Although a member of the mint family, it has been said to taste like raw kale. But for cattle, hebit can cause grass tetany, or “staggers,” (a metabolic disease involving magnesium deficiency, which can occur in ruminant animals, usually after grazing on rapidly growing pastures).
Kochia was introduced to the United States around the early 1900s from the temperate regions of Europe and Asia. Kochia seed was likely located in a contaminated commodity or livestock feed making the trip by ship to the North American east coast. Kochia had spread across the U.S. and Canada by the 1930s, primarily by wind blowing mature plants across the soil, releasing seed as it rolls (which is why Kochia is often referred to as tumbleweed). It is now considered a noxious weed in several states. Kochia can have a high forage value at its early growth stages and has another common name—poor man’s alfalfa. Kochia was used extensively as livestock feed during the drought years of the 1930’s. Young kochia plants can be toxic to mammals if plants are allowed to accumulate high levels of nitrates. Songbirds and Upland birds benefit from kochia as a nesting material, protection from predators, as a food source by attracting insects, and as a food source from its seeds.
Lambsquarters weeds are in the same goosefoot family as spinach and beets. It can have a good food value to humans, providing iron, protein, and vitamins B2 and C. Because of its food quality, some have said that it was introduced to North America by early settlers from Europe. Romans and Europeans considered Lambsquarters the most delicious wild vegetable. It was consumed raw or boiled and dried seeds ground into flour and unused plant parts served as fodder for livestock. Native Americans were known to consume Lambsquarters in similar ways.
Marestail, or horseweed, is native to North America. This is a weed we gave to Europe, causing issues of control for them. Marestail contains volatile oils and acids which are irritants to the skin and mucous membranes of humans and livestock, particularly horses.
Palmer amaranth and most pigweed species are native to North America. This weed is capable of hybridizing between species, making control over all pigweed species difficult. Palmer amaranth provides cover and seed for birds and a small feed value to cattle. It is a prolific weed that is responsible for large losses of yield for many row crops. Native Americans collected pigweed seed, consuming raw seeds and also grinding the dried seeds into flour. Young pigweed plants were boiled and eaten.
Purple Loosestrife is considered a noxious weed due to its prolific reproduction ability and difficulty to control. It arrived in North America in the early 1800s as ballast on ships from Europe and also as an ornamental plant that demonstrated medicinal qualities. Its flowers offer nectar to bees for honey production. Several states have actually seeded roadsides with purple loosestrife seed in an effort to control erosion, but wildlife habitat can be destroyed by this weed if left unchecked. Purple loosestrife flowers were used as medicine to treat digestive issues and skin infections.
Velvetleaf was intentionally introduced to the North America in the early 1700s from India. It was brought here to provide fiber to produce rope, paper and caulk for ships. Due to the demand of fiber, colony farmers actually cultivated fields of velvetleaf and continued to do so for over 100 years. Today, a few dried plants are used in floral arrangements and seeds provide food for birds.
Some weeds have properties that make them useful in one form or another, but all of the weeds mentioned above have some attributes in common:
— Require control measures to contain their populations
— Has developed resistance to one or more modes of action herbicides
— Has deceased yield or land value when populations are left unchecked