Tall Hawkweed
Tall Hawkweed
Hieracium piloselloides Vill.
Asteraceae (Sunflower Family)
▲ mature flowering plant
▲ ▼ flowering stems
▲ base of plant, showing narrow leaves
Hieracium piloselloides Vill., Tall Hawkweed: (Bayer Code: HEIPO; US Code HIPI2)
- European native, simple perennial weed with a taproot that produces leafless to nearly leafless stems 6-30 inches tall above a rosette of clustered leaves; stems have many stiff, outspread hairs, many with darker glands at their base, particularly in upper portion of the stems
- Basal rosette leaves are medium to light green, alternate, with pointed or round-pointed tips; leaves usually hairless except for long white hairs along the midvein on the leaf underside, and along the smooth leaf margins; leaves have short or no petioles
- Head inflorescences are 0.5 to 1 inch in diameter, dandelion-like, in clusters at tips of usually leafless stems (occasionally one or two leaves on stem near basal rosette); heads have no disk flowers, but 60-80 yellow ray flowers; the yellow “petals" have 4 notches in their flattened tips
- A single row of bracts below the head form a cylindrical to barrel-shape; individual bracts are green, linear, with pointed tips; bracts have a center ridge of black, gland-based hairs; stems just below the heads have the same black hairs
- Flowering is from mid-spring through late summer
- After flowering the florets from the head become a globe of white hairs from the pappus (parachute-like hairs) attached to small, brown to black, mature seed/fruit
- Prefers low-fertility, acidic, sandy soils; found in lawns, cultivated fields, pastures, prairies, non-crop areas, right-of-ways
- More common in northern Midwest, and is a problem due to its ability to rapidly reproduce by seed
- Similar species:
- Orange Hawkweed (Hieracium aurantiacum) looks very similar to yellow hawkweed in leaf shape, growth form and height, except it has orange to red-orange florets in its flower heads
- Yellow Hawkweed (Hieracium caespitosum) looks very similar to orange hawkweed in leaf shape, growth form and height, except it has bright yellow florets in its flower heads
- Common Catsear (Hypochaeris radicata) has similar yellow flowers, but has a more branched, open clustering of flower heads, and individual heads have long supporting stalks; also the basal rosette leaf margins of common catsear are widely lobed, not smooth or toothed, as with yellow hawkweed
- Smooth Hawksbeard (Crepis capillaris) has similar, but smaller, yellow flowers, but they are in larger, more open clusters; plus stems and basal leaves are hairless, and basal leaves have deep, pointed lobes, and there are smaller leaves along the flowering stems
- Dandelion (Taraxacum officinale) has similar flowers, but has nearly hairless, deeply toothed rosette leaves, and flowering stems are single, pale green to pinkish, hollow and leafless
(Updated November 25, 2022)