Hairy bittercress is an annual weed that can spread quickly. Your access to this site has been limited by the site owner If you think you have been blocked in error, contact the owner of this site for assistance. If you are a WordPress user with Datura, a night-blooming flower sometimes raised in home gardens, is also known as Jimsonweed or Thornapple (Datura stramonium). Jimsonweed is a contraction of Jamestown and is the name that early settlers and British soldiers gave the plants. Thornapple is an appropriate common name because it aptly describes the …
Hairy bittercress: A weed to watch out for
Hairy bittercress is an annual weed that can spread quickly.
Flowers and seed pods of hairy bittercress. Photo by Lori Imboden, MSU Extension.
Have you recently noticed plants with small, white flowers on the edges of your lawn, flowerbeds and rock pathways? During April and May, populations of the winter annual weed hairy bittercress (Cardamine hirsuta) become increasingly visible. Hairy bittercress has a low growing rosette similar in form to a dandelion. It raises its profile in early spring with the appearance of flowers and seeds on a vertical stem. Like many members of the mustard family, hairy bittercress sets seed prolifically. It grows quickly and a few plants or seeds can generate a more widespread infestation in even a year’s time.
The first true leaves of hairy bittercress are heart shaped. Photo by Erin Hill, MSU.
Hairy bittercress is a winter annual weed. Its seeds germinate in fall beginning as early as September. The first true leaves are heart-shaped, followed by compound leaves with two or more pairs of leaflets and a kidney shaped terminal leaflet. The leaves that emerge in the fall form a small rosette that will overwinter. Once the weather warms in spring, it sends up stalks of small, white flowers followed by slender seed pods known as siliques.
Hairy bittercress leaves have two or more pairs of leaflets and a kidney shaped terminal leaflet. Photo by Lori Imboden, MSU Extension.
Once the seed pods ripen, disturbing the pods can propel the seeds as far as 16 feet from the mother plant. This seed dispersal adds to the soil seed bank and primes the area for another infestation to emerge in early fall. After setting seed, the life cycle is complete and the plants die. Hairy bittercress and other winter annual weed species, like common chickweed and purple deadnettle, are not typically present during the summer months.
Once the seed pods ripen, disturbing the pods will send the seeds flying as far as 16 feet. Photo by Lori Imboden, MSU Extension.
Hairy bittercress is best managed mechanically when it is young. Remove it by hand, hoe or tillage in early fall or early spring before it sets seed. If plants are flowering, composting is discouraged as seeds may develop. To manage this weed using herbicides, the proactive approach would be to use a pre-emergence herbicide in the late summer (late August to early September) to target the plants at the time of germination and prevent successful emergence.
If plants have already emerged, applying a post-emergence herbicide to actively growing plants before seedpods form may be effective. If using an herbicide, be certain it contains an active ingredient that will target this weed. Always read and follow all labeled instructions to increase effectiveness and prevent personal or environmental harm.
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What Weed Has a Round Prickly Seed Pod?
Datura, a night-blooming flower sometimes raised in home gardens, is also known as Jimsonweed or Thornapple (Datura stramonium). Jimsonweed is a contraction of Jamestown and is the name that early settlers and British soldiers gave the plants. Thornapple is an appropriate common name because it aptly describes the round, prickly seedpod that develop after the spent flowers fall off the plant. The prickly seedpods prevent animals from eating the toxic seeds.
Jimsonweed grows to heights of between 1 and 5 feet. Its leaves’ edges are toothed edges and nearly egg shaped with pointed ends. Their length ranges from 2 to 8 inches. Funnel-shaped flowers are 2-1/2 to 4 inches long and open to a trumpetlike bell in white, violet or lavender. The plant’s fruit is a spiny pod measuring roughly 2 inches in diameter. The seedpods grow as they ripen and the seeds mature. Ripe seedpods burst open, scattering the seeds.
- Jimsonweed grows to heights of between 1 and 5 feet.
- Its leaves’ edges are toothed edges and nearly egg shaped with pointed ends.
Most species are low-growing, shrublike or spreading perennials or are prolifically reseeding annuals. D. wrightii is the species that is common to the Western United States. Rank-smelling leaves and large, white flowers that are occasionally tinged with purple characterize this plant. A sprawling perennial, the plants have enormous taproots that may extend deeper than 2 feet into the ground. Its geographic range extends from California to Utah, Arizona, New Mexico and into Texas. D. wrightii is considered a cosmopolitan annual weed that seeds prolifically. D. discolor is a native species found in riverbeds and desert washes in Arizona and southeastern California. It has smaller flowers. D, stramonium is naturalized throughout the United States. D. stramonium is distinguished from D. wrightii because the plants have smaller flowers and a more erect growing habit.
- Most species are low-growing, shrublike or spreading perennials or are prolifically reseeding annuals.
- D. discolor is a native species found in riverbeds and desert washes in Arizona and southeastern California.
The contraction of “Jamestown weed” is the origin of the name Jimsonweed. Soldiers and settlers were poisoned after eating the plant’s leaves in salads. Long ago in India and Russia, robbers would grind up the seeds of Jimsonweed and mix them with water as a way to sedate, induce amnesia or daze people they intended to victimize and rob. Members of the ancient Indian religious order that worshipped Kali, the goddess of destruction, would also grind the seeds and feed them to people before robbing and/ murdering them. In China, Jimsonweed was prescribed for the sedative effects, for foot diseases and used for flatulence.
All parts of Datura or Jimsonweed are poisonous. Keep places where livestock graze free of the plant. Ridding an area of plants is difficult and time consuming because of the ease with which seeds spread. Some people may experience skin irritation from contact with these plants, so wear protective clothing or gear. Symptoms of Jimsonweed poisoning include blurred vision, confusion, dilated pupils, dry mouth, difficulty urinating, hallucinations and tachycardia. Although it rarely causes death, later signs of toxicity may include coma and seizures. Emergency medical attention is necessary in cases of suspected Jimsonweed poisoning. Poisoning is treated with activated charcoal and gastric lavage. Severe sinus tachycardia is treated with beta-blockers.