According to observations of naturalists and beekeepers.
Where are you?
30 kilograms per ha
SOURCE FOR HONEY BEES:
Major in some areas
Smooth blackberry's range extends from Newfoundland to Ontario and along the Atlantic Coast south to Georgia and inland to Kentucky and Tennessee.
Smooth blackberry is a common understory species in open deciduous forests, on mountain ridges, and in disturbed areas.
This plant is present in at least 28 states/provinces in this country.
This rhizomatous shrub forms thickets up to 2 to 3 meters (7–10 feet) tall. The leaves are deciduous and alternately arranged, each measuring 10 to 20 centimeters (4-8 inches) long. The inflorescence is a cluster of up to 25 flowers. The fruit is an aggregate of many small drupes, each of which contains a tiny nutlet. The plant reproduces by seed, by sprouting up from the rhizome, and by layering. The stems can grow one meter (40 inches) in height in under two months.
Smooth blackberry grows across a wide range of sites throughout the cool, moist climate of the Northeast. It is very common in woods, old fields, cool hollows, and along roadsides.
Smooth blackberry flowers from May to June. Fruits ripen in early summer and persist into September. The seed disperses in September.
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)
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)
Asclepias syriaca (aka: Сommon milkweed, Butterfly flower, Silkweed, Silky swallow-wort, Virginia silkweed)
Brassica rapa (aka: Field mustard, Common mustard, Wild mustard, Wild turnip, Forage turnip, Wild rutabaga, Birdsrape mustard, Rape mustard)
Echium vulgare (aka: Viper's bugloss, Blueweed, Blue thistle)
Salsola kali (aka: Russian thistle, Tumbleweed, Prickly saltwort)
Cucumis sativus (aka: Cucumber, Cetriolo, Gherkin)
Cucumis melo (aka: Cantaloupe, Rockmelon, Sweet melon, Spanspek, Honeydew melon, Honeymelon, Crenshaw, Casaba)
Citrullus lanatus (aka: Watermelon)
Cephalanthus occidentalis (aka: Common buttonbush, Buttonball, Buttonbush, Button willow, Riverbush, Honey-bells)
Aralia spinosa (aka: Devil's walkingstick, Prickly ash, Hercules club, Angelica tree, Prickly elder, Pick tree, Toothache tree, Shotbush)
Asteraceae (aka: Aster, Daisy, Composite)