According to observations of naturalists and beekeepers.
Where are you?
Littletree willow occurs in central Alaska, the Yukon Territory, and adjacent Northwest Territories eastward throughout the boreal forest to Hudson Bay. It extends southward in the eastern Rocky Mountains to northeastern British Columbia, northern Alberta, Saskatchewan, and Manitoba. Littletree willow does not occur in the contiguous United States.
This plant is present in at least 10 states/provinces in this country.
Acer saccharinum (aka: Silver maple, Soft maple)
Acer negundo (aka: Boxelder, Western boxelder, Arizona boxelder, California boxelder, Texas boxelder, Interior boxelder, Violet boxelder)
Salix lucida (aka: Shining willow, Greenleaf willow, Tail-leaf willow, Whiplash willow, Pacific willow, Lance-leaf willow, Longleaf willow, Red willow, Western shining willow)
Ulmus americana (aka: American elm, White elm, Water elm, Soft elm, Florida elm)
Crataegus douglasii (aka: Black hawthorn, Douglas hawthorn, River hawthorn, Western thornapple)
Salix exigua (aka: Narrowleaf willow, Coyote willow)
Populus tremuloides (aka: Quaking aspen, Trembling aspen, Aspen, American aspen, Mountain aspen, Golden aspen, Trembling poplar, White poplar, Popple, Alamo Blanco)
Salix scouleriana (aka: Scouler's willow, Upland willow)
Prunus pumila (aka: Sandcherry, Western sandcherry, Eastern sandcherry, Great Lakes sandcherry)
Salix arbusculoides (aka: Littletree willow)
Salix bebbiana (aka: Bebb willow, Beak willow, Beaked willow, Long-beaked willow, Diamond willow, Chaton, Petit Minou, Smooth Bebb willow)
Salix discolor (aka: Pussy willow, American pussy willow, Glaucous willow, Large pussy willow)
Prunus americana (aka: American plum, Goose plum, River plum, Wild plum)