According to observations of naturalists and beekeepers.
Where are you?
Yellow willow is found at low to mid-elevations from Alberta to Manitoba, south to western Kansas and New Mexico, west to Arizona and California, and north along the Sierra Nevada Mountains to eastern Washington. It is lacking in the Great Basin.
This plant is present in at least 21 states/provinces in this country.
Yellow willow is a deciduous shrub, or rarely, a small tree up to 23 feet (7 m) tall, with stems diameters up to 8 inches (20 cm). The silvery-gray bark of older twigs distinguishes it from many closely related willows. The leaves are alternate, simple, pinnately veined, mostly lanceolate, with finely serrate margins, dark green to yellow-green above and pale or glaucus beneath, with conspicuous stipules usually present. Male and female flowers occur on separate plants as catkins. Staminate catkins are .8-2 inches (2-5 cm) long, and pistillate catkins are .8-2.7 inches (2-7 cm) long, but mostly under 1.5 inches (4 cm).
Yellow willow is a deciduous shrub or rarely small tree. Its catkins emerge before and with the leaves in the spring. After fruits ripen, seeds are dispersed from spring to early summer.
Sinapis arvensis (aka: Charlock mustard, California rape, Charlock, Corn mustard, Canola, Kaber mustard, Rapeseed mustard)
Agastache foeniculum (aka: Giant hyssop, Blue giant hyssop, Anise hyssop, Fragrant giant hyssop, Lavender giant hyssop)
Borago officinalis (aka: Borage, Starflower, Common borage, Cool-tankard, Tailwort)