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.
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 emarginata (aka: Bitter cherry)
Prunus pumila (aka: Sandcherry, Western sandcherry, Eastern sandcherry, Great Lakes sandcherry)
Salix bebbiana (aka: Bebb willow, Beak willow, Beaked willow, Long-beaked willow, Diamond willow, Chaton, Petit Minou, Smooth Bebb willow)
Salix scouleriana (aka: Scouler's willow, Upland willow)
Acer platanoides (aka: Norway maple)
Rubus ursinus (aka: California blackberry, California dewberry, California grapeleaf dewberry, Douglasberry, Pacific blackberry)
Salix lemmonii (aka: Lemmon's willow, Lemmon willow)
Salix planifolia (aka: Diamondleaf willow, Planeleaf willow)
Salix boothii (aka: Booth's willow)
Robinia pseudoacacia (aka: Black locust, False acacia, Yellow locust, White locust, Green locust, Post locust, Falsa acacia, Robinia)
Rhamnus cathartica (aka: Common buckthorn, European buckthorn, Dahurian buckthorn)
Astragalus (aka: Milkvetch, Locoweed, Goat's-thorn)
Populus tremuloides (aka: Quaking aspen, Trembling aspen, Aspen, American aspen, Mountain aspen, Golden aspen, Trembling poplar, White poplar, Popple, Alamo Blanco)
Rubus laciniatus (aka: Cutleaf blackberry, Evergreen blackberry, Slashed blackberry)
Salix lutea (aka: Yellow willow)
Salix geyeriana (aka: Geyer willow, Silver willow)
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)
Prunus pensylvanica (aka: Pin cherry, Fire cherry, Bird cherry)
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)
Prunus virginiana (aka: Chokecherry, Western chokecherry, Common chokecherry, Black chokecherry)
Salix glauca (aka: Grayleaf willow, Gray willow, Gray-leaved willow)
Salix brachycarpa (aka: Shortfruit willow, Barren-ground willow, Small-fruit sand dune willow, Small-fruit willow)
Rubus parviflorus (aka: Thimbleberry, Western thimbleberry)
Rubus armeniacus (aka: Himalayan blackberry, Rubus discolor, Rubus procerus)
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)
Echium vulgare (aka: Viper's bugloss, Blueweed, Blue thistle)
Brassica rapa (aka: Field mustard, Common mustard, Wild mustard, Wild turnip, Forage turnip, Wild rutabaga, Birdsrape mustard, Rape mustard)
Asclepias syriaca (aka: Сommon milkweed, Butterfly flower, Silkweed, Silky swallow-wort, Virginia silkweed)
Agastache foeniculum (aka: Giant hyssop, Blue giant hyssop, Anise hyssop, Fragrant giant hyssop, Lavender giant hyssop)
Chamaenerion angustifolium (aka: Fireweed, Great willowherb, Rosebay willowherb, Saint Anthony's Laurel, French-willow)
Borago officinalis (aka: Borage, Starflower, Common borage, Cool-tankard, Tailwort)
Cucumis melo (aka: Cantaloupe, Rockmelon, Sweet melon, Spanspek, Honeydew melon, Honeymelon, Crenshaw, Casaba)