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.
Acer saccharinum (aka: Silver maple, Soft maple)
Pyrus communis (aka: European pear, Common pear)
Acer negundo (aka: Boxelder, Western boxelder, Arizona boxelder, California boxelder, Texas boxelder, Interior boxelder, Violet boxelder)
Salix nigra (aka: Black willow, Swamp willow, Southwestern black willow, Gulf black willow, Scythe-leaved willow)
Salix lucida (aka: Shining willow, Greenleaf willow, Tail-leaf willow, Whiplash willow, Pacific willow, Lance-leaf willow, Longleaf willow, Red willow, Western shining willow)
Prunus cerasus (aka: Sour cherry, Tart cherry, Dwarf cherry, Montmorency cherry)
Prunus pumila (aka: Sandcherry, Western sandcherry, Eastern sandcherry, Great Lakes sandcherry)
Liriodendron tulipifera (aka: Tuliptree, Blue-poplar, Tulip-poplar, Yellow-poplar, Yellow wood)
Salix bebbiana (aka: Bebb willow, Beak willow, Beaked willow, Long-beaked willow, Diamond willow, Chaton, Petit Minou, Smooth Bebb willow)
Ulmus americana (aka: American elm, White elm, Water elm, Soft elm, Florida elm)
Malus domestica (aka: Pyrus pumila, Malus pumila, Apple)
Acer platanoides (aka: Norway maple)
Acer saccharum (aka: Sugar maple, Rock maple, Hard maple)
Celtis occidentalis (aka: Common hackberry, Bastard elm, Nettle-tree, Northern hackberry)
Catalpa speciosa (aka: Northern catalpa, Hardy catalpa, Western catalpa, Cigar tree, Catawba-tree, Bois chavanon)
Rubus canadensis (aka: Smooth blackberry, Thornless blackberry, Canadian blackberry, Smooth highbush blackberry)
Rubus idaeus (aka: Raspberry, Black-haired red raspberry, Brilliant red raspberry, American red raspberry, Red raspberry, Smoothleaf red raspberry, Wild raspberry, Wild red raspberry, Grayleaf raspberry)
Acer pensylvanicum (aka: Striped maple, Moosewood, Goosefoot maple, Whistlewood)
Acer spicatum (aka: Mountain maple, Low maple, Moose maple, Water maple, Plaine batarde, Fouereux)
Astragalus (aka: Milkvetch, Locoweed, Goat's-thorn)
Ajuga reptans (aka: Bugle, Blue bugle, Bugleherb, Bugleweed, Carpetweed, Carpet bugleweed, Common bugle, St. Lawrence plant)
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)
Rhus glabra (aka: Smooth sumac, Common sumac, Rocky Mountain sumac, Red sumac, Western sumac, White sumac)
Allium schoenoprasum (aka: Chives)
Brassica napus (aka: Rapeseed)
Sinapis arvensis (aka: Charlock mustard, California rape, Charlock, Corn mustard, Canola, Kaber mustard, Rapeseed mustard)
Gleditsia triacanthos (aka: Honey locust, Honey shucks locust, Common honeylocust, Sweet bean locust)
Rubus phoenicolasius (aka: Wine raspberry, Japanese wineberry, Wineberry)
Aronia melanocarpa (aka: Black chokeberry, Rowan, Mountain Ash, Sorbus)
Prunus serotina (aka: Black cherry, Wild black cherry, Rum cherry, Mountain black cherry, Wild cherry)
Prunus pensylvanica (aka: Pin cherry, Fire cherry, Bird cherry)
Robinia pseudoacacia (aka: Black locust, False acacia, Yellow locust, White locust, Green locust, Post locust, Falsa acacia, Robinia)
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)
Rhamnus cathartica (aka: Common buckthorn, European buckthorn, Dahurian buckthorn)
Salix planifolia (aka: Diamondleaf willow, Planeleaf willow)
Tilia americana (aka: American basswood, Basswood, Linden)
