Introduced species: Thistles–“Canada” and bull thistle (Circium arvense and C. vulgare), Italian and Scotch thistles (Carduus pycnocephalus and Onopordum acanthium) Characteristics: Thistles are members of the sunflower (aster) family. Canada (or […]
Introduced species: Armenian blackberry (Rubus bifrons) This month’s weed is no stranger to anyone who’s spent much time in the Pacific northwest; whether you’ve been scratched by its prodigious thorns*,
Introduced species: Garlic Mustard (Alliaria petiolata) Characteristics: Garlic mustard is an herbaceous “biennial” (more on that in a minute) with a deep, white taproot. The rosettes, formed in the first
Introduced species: Italian Arum (Arum italicum) Characteristics: Italian Arum—a.k.a. Lords and Ladies—is a tuberous perennial, growing to 12 inches high. It has glossy, arrow-shaped leaves up to 14 inches long,
Introduced species: Hairy bittercress (Cardamine hirsuta) Description: This month’s weed is less of a threat to natural areas than many featured weeds–though it does show up there–but is one that