The Enemy: Yellow or Meadow Hawkweed (Hieracium caespitosum) is a native plant to Europe. It appears to have been spread by people who love the beautiful yellow – dandelion like flowers. The problem is that the plant spreads not only by seed (up to 250 yards) but also by stolons (above ground) and rhizomes (below ground) which means this plant can spread almost anywhere it wishes. The native Hawkweeds do not produce stolons or rhizomes. Plants produce a basal rosette of leaves which produce stems that are mostly leafless. The stems have black hairs on them that give them a darker look from afar. The surface below the flowers also contain the black hairs that will make the entire bud look black. The stems and leaves exude a milky latex when cut or broken. This plant has not been found in our area but is abundant in northern Idaho counties, western Wyoming, and Washington State.
The Strategy: This plant generally inhabits riparian areas (streams, ditches, and the like) but mostly it likes moist grasslands or forest edges. As the plant is built to develop anywhere and spreads even worse, it is extremely competitive toward the desirable species. Livestock will not graze on the plant therefore like many other weeds they tend to overgraze the desirable plants which allows the invader to grow stronger.
The Defense: Mechanical control is not much of an option when dealing with established weeds of this type. If there is just one or two plants then by all means please just dig them up. Once the plants become established then one needs to use specialty herbicides such as Milestone, Chaparral, Transline, Curtail, or Redeem. Apply in the spring when the plants are young, or in the fall when they are preparing for the winter. To find these products or for proper identification call your local county weed superintendent.
PLEASE NOTE – The proper use and application of herbicides can be an effective way to control and eradicate noxious and invasive plants. Before using herbicides, always carefully follow the label and safety instructions on the label. While we recommend the use of herbicides as one of the effective tools for integrated pest management, the Idaho Weed Awareness Campaign assumes no liability for herbicide applications.