Try to pull out this weed before it flowers!
Using an organic mulch such as wood chips, at least two inches deep, will reduce the amount of weed seeds germinating by limiting light and serving as a physical barrier. Synthetic mulches such as landscape fabrics may also be used. In landscaped areas, they should be covered with an additional layer of mulch (rock or bark). Vegetable gardens also can utilize black plastic, both as mulch into which seeds or transplants are placed and also between rows.
The first plants need to be destroyed by pulling or hoeing before they become securely rooted. Look for Canada thistle above ground in early spring.
9. Pigweed (Amaranthus spp.)
Buckhorn Plantain. Photo by Oregon State University.
This weed appears from mid-spring through summer when the ground is warm. It grows well under dry, hot conditions.
To learn more about combating common garden weeds, see Weed Control Techniques, as well as our mulching guide.
Common chickweed is often forms a dense mats and rarely grows higher than 2 inches. The flowers are small with five white petals. Common chickweed will grow in a wide range of soils but does particularly well in neutral pH soils with high nitrogen and poorly in low pH or acid soils.
While burr medic can be controlled with regular mowing, this will not kill the weed. It is also tolerant of most herbicides, though non-selective types can help kill the plant as well as boiling water. Neither of these, however, will kill the burrs that are left behind in the lawn or garden.
Therefore, you may want to use an old woolen blanket to drag over the area first, which should snag most of these burrs. Then the area can be treated with a pre-emergent, such as corn gluten meal, to prevent germination of any seeds left behind. Late summer or early fall is a good time to do this.
You can recognize this weed by its green serrated leaves and reddish purple colored stems that creep closely along the ground. It also has small yellow flowers. After flowering, the tiny green pods produce prickly burrs. These will eventually dry up and turn brown, spreading seeds everywhere.
Types of Burr Weeds
Burr medic germinates in fall and winter, and flowers in spring.
Other burr species include:
Once burr medic has been eradicated, you’ll want to improve the health of your soil to minimize its return by amending it with organic matter or compost.
Since burr medic spreads and reproduces by seed, the best way to control the weed is to remove it before it has a chance to set its seed, even better before it flowers.