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.
Cercis orbiculata (aka: California redbud, Western redbud, Arizona redbud, Judas tree, Cercis occidentalis)
Rubus ursinus (aka: California blackberry, California dewberry, California grapeleaf dewberry, Douglasberry, Pacific blackberry)
Rubus spectabilis (aka: Salmonberry)
Aesculus californica (aka: California buckeye, Buckeye, Horsechestnut)
Salix lucida (aka: Shining willow, Greenleaf willow, Tail-leaf willow, Whiplash willow, Pacific willow, Lance-leaf willow, Longleaf willow, Red willow, Western shining willow)
Salix scouleriana (aka: Scouler's willow, Upland willow)
Acer circinatum (aka: Vine maple)
Malus fusca (aka: Oregon crab, Oregon crab apple, Pacific crab apple, Western crab apple)
Salix bebbiana (aka: Bebb willow, Beak willow, Beaked willow, Long-beaked willow, Diamond willow, Chaton, Petit Minou, Smooth Bebb willow)
Salix lemmonii (aka: Lemmon's willow, Lemmon willow)
Salix lutea (aka: Yellow willow)
Astragalus (aka: Milkvetch, Locoweed, Goat's-thorn)
Salix boothii (aka: Booth's willow)
Salix geyeriana (aka: Geyer willow, Silver 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)
Rubus laciniatus (aka: Cutleaf blackberry, Evergreen blackberry, Slashed blackberry)
Rhus glabra (aka: Smooth sumac, Common sumac, Rocky Mountain sumac, Red sumac, Western sumac, White sumac)
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)
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)
Calendula officinalis (aka: Marigold, Calendula, Pot marigold, English marigold)
Prunus virginiana (aka: Chokecherry, Western chokecherry, Common chokecherry, Black chokecherry)
Salix brachycarpa (aka: Shortfruit willow, Barren-ground willow, Small-fruit sand dune willow, Small-fruit willow)
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)
Rubus parviflorus (aka: Thimbleberry, Western thimbleberry)
Amorpha fruticosa (aka: Desert false indigo, False indigo-bush, Bastard indigobush, Indigo Bush)
Brassica rapa (aka: Field mustard, Common mustard, Wild mustard, Wild turnip, Forage turnip, Wild rutabaga, Birdsrape mustard, Rape mustard)
Salix planifolia (aka: Diamondleaf willow, Planeleaf willow)
Rubus armeniacus (aka: Himalayan blackberry, Rubus discolor, Rubus procerus)
Salsola kali (aka: Russian thistle, Tumbleweed, Prickly saltwort)
Cucumis melo (aka: Cantaloupe, Rockmelon, Sweet melon, Spanspek, Honeydew melon, Honeymelon, Crenshaw, Casaba)
Citrullus lanatus (aka: Watermelon)
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)
Borago officinalis (aka: Borage, Starflower, Common borage, Cool-tankard, Tailwort)