Hairy Bittercress

Posted: September 26, 2013

Hairy Bittercress (Cardcwjine hirsute) is a broadleaf, winter annual pest introduced into this country from Asia and Europe. It has become a problem in nurseries and can be found ¡n containers.

Once this pest makes its way into your yard, it can spread rapidly because one plant can project 5,000 seeds from the silique, a narrow capsule that is designed to release the seed in an explosive manner as far as ten feet away. Hand pulling while the plant is fruiting causes this explosion of seeds.

In order to control the spread, the goal is to decrease the seed production. If you haven’t hand-pulled in the spring before seed production or used a pre-emergent, spot spray of glyphosate or broadleaf herbicide, now is the time to use a post-emergent, since the plant is sensitive to herbicides. Post-emergents include 2-4D,triclopyr (Chaser), Snapshot, Metsulfuron (Blade), or Speedzone (tri-mec and Quicksilver). Sureguard (Flumioxazin)is a pre-emergent, post-emergent herbicide that is used in nursery settings as well as landscapes. Follow the directions on product labels carefully.

Using good cultural practices to encourage thick turf will discourage germination of these and other weed seeds. Follow up in the spring by using a pre-emergent and hand pull before seed production. To protect garden beds, cover with three to four inches of mulch in the spring.

Peg Jones, Penn State Master Gardener – Luzerne County