Common chickweed

Common chickweed

Fall Weed Control: Common chickweed — all-season annual

The issue: Common chickweed (Stellaria media) prefers cool, moist, shady conditions. It mostly germinates in the fall and spring, but in cool summers it germinates almost all season long. Fall seedlings will begin blooming in early spring. The tiny, white flowers have five deeply lobed petals, giving the appearance of 10 petals. The egg-shaped leaves (with a point) are bright-green and slightly hairy. Common chickweed usually forms dense mats. It reproduces by seed, but spreading stems may also root at the nodes. The main focus should be to keep it from going to seed — it only takes five weeks to go from germinated seedling to producing more seed. One plant produces 25,000 seeds on average. Common chickweed is most often found in shady lawns and flower or vegetable beds but can also invade no-till croplands.

Integrated pest management options:

· Mechanical: Hoeing or hand pulling when the soil is dry is best; fall tillage helps. Pulled plants should be thrown away. Mowing may actually spread the seeds throughout the lawn.

· Cultural: Proper lawn care to maintain a dense turf helps. Over-irrigation of lawns encourages chickweed growth. Deep mulch (greater than 3 inches) in flower beds helps.

· Biological: Ground beetles are known to eat chickweed seed.

· Chemical: Early fall application of a pre-emergent will reduce fall seedlings. Broadleaf weed control products that contain 2,4-D, dicamba, triclopyr, chlorsulfuron, or metsulfuron help with control. Some herbicides may damage landscape plants even if they are some distance away from the spray site. Be sure the target weed and crop or landscape situations are listed on the product label. Always read and follow herbicide label directions.

Combine them:

Seeds can remain dormant for many years, so a long-term control program is important. Combine different IPM options to help improve the effectiveness of your efforts.

For more information, contact Ron Patterson, University of Idaho Extension horticulture/agriculture educator in Bonneville County.