Wildlife, Animals, and Plants
VALUE AND USE
SPECIES: Cirsium vulgare | Bull Thistle
WOOD PRODUCTS VALUE :
IMPORTANCE TO LIVESTOCK AND WILDLIFE :
Sheep eat bull thistle seedlings or small rosettes. Rabbits eat leaves
and flowering stems, especially in winter and early spring .
Gophers and other small burrowing animals eat the roots, especially
taproots of rosettes .
Although bull thistle made up 1 percent of the total seed plant canopy
coverage in bighorn sheep wintering areas just outside Yellowstone
National Park, the bighorn sheep did not use it.
Juncos increased on a logged and burned site in western Oregon as bull
thistle presence increased .
In Europe, goldfinches and linnets feed on bull thistle seeds.
Pheasants graze on seedlings .
Because of its spiny stems and leaves, bull thistle is unpalatable to
most livestock. Domestic sheep in Australia, however, graze bull thistle
and dig for taproots .
Bull thistle palatability for livestock in several western states is as
MT ND UT WY
Cattle poor poor poor poor
Sheep poor fair fair poor
Horses poor poor poor poor
NUTRITIONAL VALUE :
The energy value and protein value of bull thistle for livestock is
poor. The food value of bull thistle for several species of wildlife in
several western states is :
UT WY MT
Elk fair good ----
Mule deer fair good poor
White-tailed deer ---- good ----
Pronghorn fair fair ----
Upland game birds good fair ----
Waterfowl poor poor ----
Small nongame birds good good ----
Small mammals good good ----
COVER VALUE :
The cover value of bull thistle for several species of wildlife in some
western states is :
Elk poor poor
Mule deer poor poor
White-tailed deer ---- poor
Pronghorn poor poor
Upland game birds fair good
Waterfowl poor poor
Small nongame birds fair good
Small mammals good good
VALUE FOR REHABILITATION OF DISTURBED SITES :
OTHER USES AND VALUES :
Bull thistle can cause hayfever .
Bull thistle is edible . The taproots of rosettes are peeled,
boiled, and eaten, or the boiled roots are dried and ground into
flour. The young stems and leaves, with spines removed, are eaten raw
or boiled as a green vegetable .
MANAGEMENT CONSIDERATIONS :
Bull thistle has been introduced in North America as a seed contaminant,
and is widely established . It infests thousands of acres of
cultivated land and pastures. Its wind-disseminated seeds and long
fleshy taproot make it a hardy weed .
Trampling by visitors in Yosemite Valley, California, favors bull
thistle. The rosette is relatively resistant to trampling. Meadows
with highest use are the most heavily infested .
Forestry: Transplanted Douglas-fir (Pseudotsuga menziesii) seedlings on
clearcuts in western Oregon grew significantly taller on plots
chemically weeded for bull thistle and other weeds than did seedlings on
control plots .
Rangeland: Sheep grazing other neighboring plants can cause increased
bull thistle infestation .
When herbivores damage bull thistle stems, there can be great reduction
in seed output unless secondary flowering stems form .
Control: The presence of tall herbs reduces bull thistle seedling
survival. When grass growth was reduced by herbicide spraying, bull
thistle increased in frequency 
Cutting bull thistles may help control it by limiting seed production.
Travel distance of wind-dispersed seeds is further with taller plants,
and decreasing plant height may limit spread . Seeds may be
released from bull thistle stems cut 5 to 10 days after their flowers
open. Such plants should be removed from the area after they are cut
Mowing effectively controlled bull thistle in meadows in Yosemite
National Park. It is most efficient to cut late in the season, when
most of the plants have bolted, but before significant numbers flower.
Plants will sprout from the stem and flower if mown too early. Plants
cut 8 inches (20 cm) or more above ground have a greater chance of
sprouting. A second sweep through, a month after the first, results in
the elimination of most flowering bull thistle .
Bull thistle roots need not be pulled or grubbed out of the soil to kill
the plant. This disturbs the soil and leads to greater infestation.
When bull thistle plants were cut at or near the soil surface, almost no
sprouting occurred. However, because a plant may remain in the rosette
stage for up to 5 years before flowering, a control program of cutting
bolted individuals may have to be continued for several years [18,23].
The most promising candidate for biological control of bull thistle in
Canada is the fruit fly Urophora stylata, which forms galls in the
flower heads. The fly is almost exclusively restricted to bull thistle
as a host .
Related categories for Species: Cirsium vulgare | Bull Thistle