According to observations of naturalists and beekeepers.
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Native to Eurasia, Russian-thistle is distributed throughout most arid and semiarid regions of the world. In North America, Russian thistle occurs from British Columbia east to Labrador and south through the conterminous United States to northern Mexico. It is most common in central and western regions of Canada and the United States, and along the Atlantic and Gulf coasts. Limited southern and eastern inland populations occur along with waste areas and railroad tracks. Russian-thistle is adventitious in Hawaii.
This plant is present in at least 32 states/provinces in this country.
Russian-thistle is an exotic, annual, erect, xerohalophytic forb. It is highly branched and rounded in form, growing from 1 to 3 feet (0.3-1 m) in height and from 1 to 5 feet (0.3-1.5 m) in diameter. The awl-shaped, spiny-tipped leaves bear small, inconspicuous flowers in the leaf axils. The small, winged seed, retained in the leaf axils until after plant death, contains no endosperm tissue but is instead comprised of a spirally-coiled, complete embryo already containing some chlorophyll. The root system consists of a taproot, reaching 0.3 foot (1 m) or more in-depth, and extensive lateral roots. Under crowded conditions, roots are shallow.
The following seasonal development has been reported for Russian-thistle: germinates: late April - August, flowers: June - August, seeds mature: August - November, plant dies: first fall frost, seeds disseminate: late fall.
Salix bebbiana (aka: Bebb willow, Beak willow, Beaked willow, Long-beaked willow, Diamond willow, Chaton, Petit Minou, Smooth Bebb willow)
Rhus glabra (aka: Smooth sumac, Common sumac, Rocky Mountain sumac, Red sumac, Western sumac, White sumac)
Brassica napus (aka: Rapeseed)
Allium schoenoprasum (aka: Chives)
Sinapis arvensis (aka: Charlock mustard, California rape, Charlock, Corn mustard, Canola, Kaber mustard, Rapeseed mustard)
Vaccinium corymbosum (aka: Highbush blueberry, High-bush blueberry, Northern highbush blueberry, Tall blueberry, Rabbiteye blueberry, Blue huckleberry, Tall huckleberry, Swamp huckleberry, High blueberry, Swamp blueberry)
Asclepias tuberosa (aka: Butterflyweed, Butterfly Milkweed, Orange Milkweed, Pleurisy Root, Chigger Flower, Canada root, Fluxroot, Indian paintbrush, Indian posy, Orange root, Orange Swallow-wort, Tuber root, Yellow milkweed, White-root, Windroot, Butterfly love)
Asclepias syriaca (aka: Сommon milkweed, Butterfly flower, Silkweed, Silky swallow-wort, Virginia silkweed)
Salsola kali (aka: Russian thistle, Tumbleweed, Prickly saltwort)
Brassica rapa (aka: Field mustard, Common mustard, Wild mustard, Wild turnip, Forage turnip, Wild rutabaga, Birdsrape mustard, Rape mustard)
Echium vulgare (aka: Viper's bugloss, Blueweed, Blue thistle)
Cirsium arvense (aka: Creeping Thistle, Canada thistle, Field thistle, California thistle, Lettuce from hell thistle, Corn thistle, Cursed thistle, Green thistle, Hard thistle, Perennial thistle, Prickly thistle, Small-flowered thistle, Way thistle, Stinger-needles)
Chamaenerion angustifolium (aka: Fireweed, Great willowherb, Rosebay willowherb, Saint Anthony's Laurel, French-willow)
Citrullus lanatus (aka: Watermelon)
Diervilla lonicera (aka: Northern bush honeysuckle, Bush-honeysuckle, Dwarf bush-honeysuckle, Herbe bleue)
Aralia spinosa (aka: Devil's walkingstick, Prickly ash, Hercules club, Angelica tree, Prickly elder, Pick tree, Toothache tree, Shotbush)
Cephalanthus occidentalis (aka: Common buttonbush, Buttonball, Buttonbush, Button willow, Riverbush, Honey-bells)