meadow hawkweed (Hieracium caespitosum)
Hieracium pratense Tausch
CONFIRMATION STATUS: Pending confirmation.
TAXONOMY: The currently accepted scientific name of meadow
hawkweed is Hieracium caespitosum Dumort. Meadow hawkweed
may hybridize with other hawkweeds in the subgenus Pilosella (e.g.,
European hawkweed (Hieracium lactucella) and mouseear hawk-
weed (Hieracium pilosella)). Manyflower hawkweed (Hieracium
floribundum Wimmer & Grab) is apparently a cross between mead-
ow hawkweed and European hawkweed.
NATIVE STATUS: Introduced, United States and Canada.
GENERAL BOTANICAL CHARACTERISTICS:
Habit: Meadow hawkweed is a rhizomatous and/or stoloniferous per-
ennial herb that exudes a milky sap when damaged. Leaves, stems, and
stolons are conspicuously hairy.
Meadow hawkweed stolons as long and leafy.
Leaves: Plants have a basal rosette and 10 to 30 flower stems that are
10 to 36 inches (25-91 cm) in height.
Flowers: A stem produces 5 to 30 yellow flowers arranged in a flat-
Fruit/Seeds: Meadow hawkweed seeds are small achenes that are 1.5
to 2 mm long and weigh approximately 0.09 mg. Seeds have a tawny
tuft of bristles at one end.
Roots: Meadow hawkweed has a shallow, fibrous root system with
short and stout to elongated rhizomes.
REGENERATION PROCESS: Meadow hawkweed reproduces by
seed and spreads vegetatively via adventitious root buds, stolons, and/
HABITAT TYPES: A summary of invasive hawkweeds reports that
sites most vulnerable to their establishment are disturbed areas, including
roadsides, mountain meadows, clearings in forest zones, cleared timber
units, permanent pastures, hayfields, and abandoned farmland. Floras
report meadow hawkweed in disturbed areas including fields, meadows,
pastures, clearings, roadsides and "waste" places. Floras also report mead-
ow hawkweed establishing in dry woods, dry woodland edges, thin wood-
lands, and streamsides.
SITE CHARACTERISTICS: Meadow hawkweed tolerates a range of
site characteristics. Meadow hawkweed prefers soils that are well drained,
coarse-textured, and moderately low in organic matter. An invasive plant
guide for the Upper Midwest reports that invasive hawkweeds prefer
sandy or gravelly soil, though the available literature documents a variety
of soil textures including gravelly silt loam with larger fragments of shale,
shallow rocky soil, and compacted gravelly soil. Regardless of soil type, it
has a strong preference for disturbed sites, particularly wet acidic soils. It
can, however, survive many low-productivity sites.
SEASONAL DEVELOPMENT: Meadow hawkweed seeds germinate
in both spring and fall, but seedlings typically have a higher survival rate
in the spring. Stolons elongate throughout the summer and give rise to
new rosettes. Plants commonly flower by late June or July, though there
is some variability in flowering dates in different parts of meadow hawk-
weed's North American range.
GENERAL DISTRIBUTION: Meadow hawkweed is native to north-
ern, central, and eastern Europe. It was likely introduced to the United
States in 1828 as an ornamental. As of 2010, meadow hawkweed occur-
red in two areas: from Georgia north through New England to Quebec
and west to Manitoba, and from Montana and Wyoming west to Oregon
and north to British Columbia.
SKY MEADOWS DISTRIBUTION: To be determined.
IMPORTANCE AND USES: Some parts of meadow hawkweed may be
consumed by wildlife and livestock. In feeding trials, meadow hawkweed
was consumed by captive woodchucks. In Ontario, meadow hawkweed
seedling emergence was not impacted by the presence of cages to prevent
seed predation, suggesting that seed predators did not feed on meadow
hawkweed seed. In old fields in west-central New York, meadow hawk-
weed experienced little insect herbivory, though it was listed as a food
plant for aphids (Aphididae) in New Jersey and a host plant of plant bugs
(Miridae) in West Virginia. Bees in Maryland visited meadow hawkweed.
Meadow hawkweed is palatable to livestock, including domestic sheep
and cattle. The small, prostrate leaves may be more easily consumed by
the small mouths of domestic sheep and domestic goats than cattle. In a
riparian area in southern New Hampshire, hatchling wood turtles hid un-
der the basal rosettes of meadow hawkweed growing on riparian sand-
Exudates from invasive hawkweed leaves or stems may cause congestive
and respiratory conditions and skin rashes in sensitive people.
Crooked Run Valley