Hawkweeds-non native

Hawkweeds, non-native Heracium spp. Sunflower family Non-native hawkweeds automatically listed as Class C weeds There are eight species of hawkweed known to be native to the state of Washington. All others have been introduced from elsewhere. Some 260 Heracium species occur in Europe and most of these should be considered as having the potential to establish as weeds in WA. Hawkweeds are notorious for being difficult to identify because of their tendency to interbreed, resulting in a puzzling variety of characters on individual plants and gradation of plant characters between populations. Because of this difficulty in positively identifying non-native hawkweeds to species, hawkweeds are now automatically listed as Class C noxious weeds if they can be shown to not be one of the eight native species.
Key identifying traits Most introduced species have short stolons (above ground runners like strawberries)-no native species do Stems of introduced species are usually progressively less leafy from the bottom to the top Biology and ecology Generally a perennial reproducing by seeds and stolons Can form very dense patches, excluding native species Native to Europe Sometimes introduced as an ornamental plant Control Prevention – Learn to identify native plants and don’t introduce other hawkweeds Biological – None known at this time-research ongoing with emphasis on stolons which are unique to invasives Cultural – Healthy native plant communities help reduce likelihood of establishment but don’t stop it-good nitrogen levels favor grass over hawkweeds Mechanical – Digging of plants is effective if enough root and stolon material is removed to prevent regrowth; mowing can stimulate growth. Chemical – Several effective at label rates; refer to the PNW Weed Management Handbook for specific chemical recommendations



*Where found –* Of the seven non-native hawkweeds specifically listed on the WA State Weed List, only 3 have been positively identified in Stevens County to date: Orange, Yellow (Meadow) and Queen-devil. None of the other 260 non-native species is known to occur here. MSdoc pdf