According to observations of naturalists and beekeepers.
Where are you?
Park willow occurs in the middle and southern Rocky Mountain region from Wyoming to New Mexico.
This plant is present in at least 5 states/provinces in this country.
Park willow is a native, erect shrub 3 to 12 feet (1.5-4 m) tall, and usually forming dense clumps. The trunk of park willow is smooth or slightly cracked. The wood is fine-grained and soft and has no sapwood-heartwood line. Park willow has a remarkable characteristic of plasticity; its growth form adapts readily to a wide variety of habitats. Branching habit and foliage characteristics vary greatly depending on site conditions.
Park willow flowers in May, before the leaves appear, through July. The fruit ripens soon after flowering, followed by seed dispersal in early to midsummer.
Salix bebbiana (aka: Bebb willow, Beak willow, Beaked willow, Long-beaked willow, Diamond willow, Chaton, Petit Minou, Smooth Bebb willow)
Salix monticola (aka: Park willow, Cherry willow, Mountain willow, Serviceberry willow, White willow)
Rhus glabra (aka: Smooth sumac, Common sumac, Rocky Mountain sumac, Red sumac, Western sumac, White sumac)
Sinapis arvensis (aka: Charlock mustard, California rape, Charlock, Corn mustard, Canola, Kaber mustard, Rapeseed mustard)
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)
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)
Salix geyeriana (aka: Geyer willow, Silver willow)
Salix planifolia (aka: Diamondleaf willow, Planeleaf willow)
Brassica rapa (aka: Field mustard, Common mustard, Wild mustard, Wild turnip, Forage turnip, Wild rutabaga, Birdsrape mustard, Rape mustard)
Rubus armeniacus (aka: Himalayan blackberry, Rubus discolor, Rubus procerus)
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)
Cephalanthus occidentalis (aka: Common buttonbush, Buttonball, Buttonbush, Button willow, Riverbush, Honey-bells)