According to observations of naturalists and beekeepers.
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Grayleaf willow grows throughout most of Alaska except for the Aleutian Islands and along the southeastern coast. It grows through much of northern Canada from Newfoundland northwest to the northern Yukon Territory, and south to southern British Columbia and Alberta. In the contiguous United States, it grows in alpine and subalpine habitats in Montana, Wyoming, eastern Idaho, Colorado, Utah, and northern New Mexico.
This plant is present in at least 20 states/provinces in this country.
Grayleaf willow commonly grows as an erect shrub 3 to 4 feet (0.9-1.2 m) tall. On exposed tundra sites it grows as a low, semi prostrate shrub, and on favorable sites, it sometimes grows up to 20 feet (6 m) in height and 5 inches (12 cm) in diameter. The bark is gray and smooth but may become rough and furrowed on larger individuals.
Male and female flowers occur on separate plants in 3/4- to 2-inch-long (2-5 cm) catkins that persist over the summer.
The fruit is a 1/32- to 1/16-inch-long (0.8-1.6 mm) two-valved capsule.
Grayleaf willow catkins appear with the leaves. In Alaska and the Yukon, flowering generally occurs in June, the fruits ripen in July and August and the seeds are dispersed in late August and September.
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)
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)
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)
Hyssopus officinalis (aka: Hyssop)