The enemy

Prickly lettuce (Lactuca serriola L). This invader from Europe has invaded our entire country. It was originally brought in as a food product to be used in salads. This annual plant grows erect to a height of 4 feet, has rounded lobed leaves that, interestingly, grow vertically toward the sun. That is, the leaves in our area only grow north and south thus collecting the cool morning and afternoon sun, but not the hot sun during the middle of the day.

This unique characteristic has given this weed the alternate name of compass weed. The leaves have a large mid-vein which have spines on the bottom side. The plant produces numerous small yellow flowers off three to five stems from the top of the plant that produce a plume which allows it to float in the air.

This weed blooms late in the summer and inhabits any disturbed site, and the seed blows in the wind. It is very aggressive in competing against crops, landscapes, and desirable vegetation along the roadsides. It is grazed on by livestock early in the season but eventually becomes very stiff and tough, thus the animals (except grasshoppers) evade it for better feed. As mentioned, the plant disperses through the wind, thus is can show up anywhere, and usually does. It especially likes to grow in disturbed areas such as over-grazed fields, empty lots, and crops.

The defense

The early growth of this plant resembles a dandelion, so it you see it simply dig it up like you would an unwanted weed. Once established it is effectively controlled utilizing simple herbicides such as 2,4-D or Dicamba. When fairly mature we go after it like we do other plants in the Asteracea family with products such as Milestone, Opensight, or Telar XP.

Just because animals like to eat it doesn’t mean that they will remove it. This plant has invaded due to disturbance so minimize your disturbance and the weed will not invade but control it once it does or it will become a menace.