According to observations of naturalists and beekeepers.
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81-161 kilograms per ha
SOURCE FOR HONEY BEES:
Aronia melanocarpa, called the black chokeberry, is a species of shrubs in the rose family native to eastern North America, ranging from Canada to the central United States, from Newfoundland west to Ontario and Minnesota, south as far as Arkansas, Alabama, and Georgia. This plant has been introduced and is cultivated in Europe.
This plant is present in at least 36 states/provinces in this country.
It is a branching shrub with glossy dark green leaves that take on a red color in the autumn; it grows well in the sun and part-shade, forming clumps by means of stems rising from the roots, its flowers are white or pink, they appear at the end of spring and produce black fruits in September.
The flowers form pollen and secrete nectar, well visited by bees.
Flowering begins in the second half of May - early June; depending on weather conditions.
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)
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)
Cucumis melo (aka: Cantaloupe, Rockmelon, Sweet melon, Spanspek, Honeydew melon, Honeymelon, Crenshaw, Casaba)
Citrullus lanatus (aka: Watermelon)
Calluna vulgaris (aka: Heather, Scotch heather, Common heather, Ling, Simply heather)
Asteraceae (aka: Aster, Daisy, Composite)