Identification of invasive yellow-flowered Pilosella hawkweeds can be very difficult and often requires expert help. Consequently, yellow-flowered invasive hawkweeds are largely lumped together in this resource.

Exotic invasive hawkweeds  are upright perennials typically growing 2 in to 2 ft tall (5–60 cm) from a fibrous root system with short rhizomes. Some hawkweeds also produce stolons up to 1 ft (30 cm) long that produce daughter plants. Stems are largely unbranched. Leaves (up to 5 in/13 cm long) typically occur only in a basal rosette, though one or two smaller leaves may occur midway up the plant stem. Stems and leaves are covered with stiff hairs that can be simple, glandular, and/or star-shaped. Leaves and stems contain a milky latex. Flower heads are ≤1 in (2½ cm) in diameter with an average of 30 yellow ray florets. Seed head bracts are covered in hairs. Seeds are topped by tufts of pappus, resembling dandelion seeds.