List of pollen sources explained

The term pollen source is often used in the context of beekeeping and refers to flowering plants as a source of pollen for bees or other insects. Bees collect pollen as a protein source to raise their brood. For the plant, the pollinizer, this can be an important mechanism for sexual reproduction, as the pollinator distributes its pollen. Few flowering plants self-pollinate; some can provide their own pollen (self fertile), but require a pollinator to move the pollen; others are dependent on cross pollination from a genetically different source of viable pollen, through the activity of pollinators. One of the possible pollinators to assist in cross-pollination are honeybees. The article below is mainly about the pollen source from a beekeeping perspective.

The pollen source in a given area depends on the type of vegetation present and the length of their bloom period. What type of vegetation will grow in an area depends on soil texture, soil pH, soil drainage, daily maximum and minimum temperatures, precipitation, extreme minimum winter temperature, and growing degree days. The plants listed below are plants that would grow in USDA Hardiness zone 5. A good predictor for when a plant will bloom and produce pollen is a calculation of the growing degree days.

The color of pollen below indicates the color as it appears when the pollen arrives at the beehive. After arriving to the colony with a fresh load of pollen, the honey bee unloads its pollen from the pollen basket located on its hind legs. The worker bees in the colony mix dry pollen with nectar and/or honey with their enzymes, and naturally occurring yeast from the air. Workers then compact the pollen. storing each variety in an individual wax hexagonal cell (honeycomb), typically located within their bee brood nest. This creates a fermented pollen mix call beekeepers call 'bee bread'. Dry pollen, is a food source for bees, which may contain 16–30% protein, 1–10% fat, 1–7% starch, many vitamins, some micro nutrients, and possibly a little sugar. The protein source needed for rearing one worker bee from larval to adult stage requires approximately 120 to 145 mg of pollen. An average bee colony will collect about 20 to 57 kg (44 to 125 pounds) of pollen a year.^{[1] [2]}

Spring

Trees and shrubs – Spring

Common name	Latin name	Blooming months	Pollen color	Availability	Source for honeybees
Maple	Acer spp.	Feb – Apr	light yellow	feral	fair
Manitoba Maple (Box elder)	Acer negundo	Feb – Apr	light olive	feral	good
Norway maple	Acer platanoides	Apr – May	yellow green, olive	feral	fair
Red Maple	Acer rubrum	Mar – Apr	grey brown	feral
Grey Alder	Alnus incana	Feb – Apr	brownish yellow	feral
American Chestnut	Castanea dentata	May – Jun		mostly ornamental
Sweet Chestnut	Castanea sativa	May		feral	good
Common Hackberry	Celtis occidentalis	Apr – May		feral
Flowering Quince	Chaenomeles japonica, Chaenomeles lagenaria, Chaenomeles speciosa 'Nivalis, Chaenomeles x superba	Apr – May		feral	good
American Hazel	Corylus americana	Mar – Apr	light green	feral and ornamental	fair/good
Hawthorn	Crataegus spp.	Apr – May	yellow brown	feral	fair
White Ash	Fraxinus americana	Apr – May
Honey Locust	Gleditsia triancanthos	May – Jun		feral
American holly	Ilex opaca	Apr – Jun		feral
Walnut	Juglans spp.	Apr – May		cultivated	fair
Tulip-tree	Lirodendron tulipifera	May – Jun	cream	feral and ornamental	good
Crab Apple	Malus spp.	Mar – Jun	light olive	ornamental
Apple	Malus domestica, Malus sylvestris	Apr – May	yellow white	cultivated and ornamental	very good
American Sycamore	Platanus occidentalis	Apr – May	light olive	feral
Plum	Prunus spp.	Apr – May	light grey, grey	ornamental and cultivated
Almond	Prunus amygdalus	Feb	light brown to brown pollen – not considered a good pollen source but bees are the primary pollinator	cultivated mostly in California	fair
Wild Cherry	Prunus avium	Apr – May	yellow brown, light brown	feral	very good
Cherry Plum	Prunus cerasifera		light brown to brown	feral	fair
Sour Cherry	Prunus cerasus	Apr – May	dark yellow	ornamental and cultivated	very good
Peach	Prunus persica	Apr – May	reddish yellow	ornamental and cultivated	good
Black Cherry	Prunus serotina	Apr – May		feral	minor
Blackthorn	Prunus spinosa	Mar – May	firebrick	feral	good
Pear	Pyrus communis	Apr – May	red yellow	ornamental and cultivated	good
Oak	Quercus spp.	May		feral
Oak	Quercus robur, Quercus pedunculata	May	light olive	feral	minor
Black Locust	Robinia pseudoacacia	May – Jun		feral
Blackberry	Rubus spp.	May – Jun	light grey	feral and cultivated
Raspberry	Rubus idaeus	May – Jun	white grey	feral and cultivated	good
Willow	Salix spp.	Feb – Apr	lemon	feral	good
White Willow	Salix alba			feral	good
Goat Willow	Salix caprea	Mar – Apr		feral	very good
Violet Willow	Salix daphnoides	Mar – Apr		feral	very good
Pussy Willow	Salix discolor	Mar – Apr		feral and ornamental
Basket Willow	Salix purpurea	Mar – Apr		feral	very good
Silky leaf osier, Smith's Willow	Salix x smithiana	Apr – May			very good
American mountain ash	Sorbus americana	May-Jun		feral
American Elm	Ulmus americana	Feb – Apr	light grey	feral
Winged Elm	Ulmus alata	Feb – Mar	pale yellow	feral	good
European field elm	Ulmus minor			feral	good

Gallery

Flowers and annual crop plants – Spring

Common name	Latin name	Blooming months	Pollen color	Availability	Source for honeybees
Ajuga (Bronze Bugle, Common Bugle)	Ajuga reptans	mid spring
Chives	Allium schoenoprasum	May – Sep		cultivated?
Asparagus	Asparagus officinalis	May – Jun	bright orange	cultivated
Mustard	Brassica arvenisi	Apr – May	lemon	cultivated and feral
Canola (Oilseed Rape)	Brassica napus	May – Jun	lemon	extensively cultivated	very good
Yellow Crocus	Crocus vernus (syn. Crocus aureus)	April	orange yellow	feral and ornamental	fair
Leopard's Bane	Doronicum cordatum	Apr – May
Winter aconite	Eranthis hyemalis	Mar – Apr	yellow	feral and ornamental	good
Snowdrop	Galanthus nivalis	Mar – Apr	orange, red		fair
Henbit	Lamium amplexicaule	April	orange red, red, purplish red	Apr – Jul	poor
Common Mallow	Malva sp.	Apr – Sep	mauve	feral	good
White Sweet Clover	Melilotus alba	May – Aug	yellow to dark yellow	feral and cultivated	good
Yellow Sweet Clover	Melilotus officinalis	May – Aug	yellow to dark yellow	feral and cultivated
Sainfoin	Onobrychis viciifolia	May – Jul	yellow brown		very good
Siberian squill	Scilla siberica	Mar – Apr	steel blue	feral and ornamental	good
White mustard	Sinapis alba	June	lemon	feral and cultivated	good
Chick weed	Stellaria media	Apr – Jul	yellowish	feral	minor
Dandelion	Taraxacum officinale	Apr – May	red yellow, orange	feral	very good
Gorse	Ulex europaeus	Mar – Dec	light firebrick	feral	good

Summer

Trees and shrubs – Summer

Common name	Latin name	Blooming months	Pollen color	Availability	Source for honeybees
Red Horse chestnut	Aesculus carnea		raisin ^[3]	feral
Horse chestnut	Aesculus hippocastanum	May – Jun after 80-110 growing degree days.	anatolia	feral	good
Southern Catalpa	Catalpa bignonioides	Jun – Jul		ornamental	fair
Northern Catalpa	Catalpa speciosa	Jun – Jul		ornamental
Bluebeard	Caryopteris x clandonensis 'Heavenly Blue'	Aug – Sep			very good
Virginia creeper	Parthenocissus quinquefolia	Jul – Aug			good
Boston Ivy 'Veitchii'	Parthenocissus tricuspidata 'Veitchii	Jun – Jul			good
Sumac	Rhus glabra	Jun – Jul
Elder	Sambucus canadensis	Jun – Jul	canary yellow
Basswood or American Linden	Tilia americana	Jun – Jul	yellow to light orange	feral and ornamental
Little Leaf Linden	Tilia cordata		citrine	feral
Blueberry	Vaccínium myrtíllus	Jun	red yellow, orange	cultivated	poor

Flowers and annual crop plants – Summer

Common name	Latin name	Blooming months	Pollen color	Availability	Source for honeybees
Allium	Allium spp.			feral and cultivated
Onion	Allium cepa		light olive	cultivated
Chives	Allium schoenoprasum	May – Sep		feral and cultivated
Garlic chives	Allium tuberosa	Aug – Sep		feral and cultivated
Leadwort syn. Indigobush	Amorpha fruticosa	Jun – Jul		ornamental?
Aster	Aster spp.	Sep-Frost	reddish yellow	feral and ornamental
Land-in-blue, Bushy Aster	Aster x dumosus	Aug – Sep	bronze yellow	feral
Borage	Borago officinalis	Jun – Frost	blueish grey	ornamental
Marigold	Calendula officinalis	Jun – Sep	orange
Heather sp.	Calluna vulgaris	Jul – Aug	yellow white, white		good
Hemp	Cannabis sativa	Aug	yellow green		good source
Blue Thistle	Carduus spp.
Star thistle	Centaurea spp.	Jul – Sep
Persian centaurea	Centaurea dealbata		hemp
Knapweed	Centaurea macrocephala	Jul – Aug			good
Knapweed	Centaurea nigra		very light olive
Chicory	Cichorium intybus L.		white
Cotoneaster	Cotoneaster spp.				good
Cucumber	Cucumis spp.		pale yellow	cultivated
Melons	Cucumis melo	Jun-Frost	pale yellow	cultivated
Pumpkin	Cucurbita pepo	Jun-Frost	bright yellow	cultivated
Fireweed (Rosebay Willowherb)	Epilobium angustifolium	Jul – Aug	blue	feral
Joe-Pye weed, Bluestem	Eutrochium spp.; Eupatorium purpureum	Aug – Sep	bistre green
Buckwheat	Fagopyrum esculentum	Jul – Aug	light yellow to light green	cultivated	good source
Blue vine	Gonolobus laevis syn. Cynanchum laeve
Sunflower	Helianthus annuus	Jun – Sep	golden	feral and cultivated
Jewelweed	Impatients capensis		yellowish white
Alyssum	Lobularia maritima	Jun – Sep
Lupin	Lupinus sp.	Jun – Jul	white, yellow or blue		minor
Mallow	Malva sylvestris	Jun – Sep
Alfalfa	Medicago sativa	July – Aug	khaki	feral and cultivated
Clover	Melilotus spp. and Trifolium spp.	May – Aug		feral and cultivated
White Sweet Clover	Melilotus alba		auburn	feral and cultivated
Yellow Sweet Clover	Melilotus officinalis		auburn	feral and cultivated
Basil	Ocimum basilicum		white	ornamental
Poppy	Papaver orientale	May – Jul	blueish grey	ornamental only	good source ^[4]
Opium poppy	Papaver somniferum	May – Jun	grey	feral and ornamental	very good source
Phacelia	Phacelia tanacetifolia	Jun – Sep	navy blue	feral and cultivated	good source
Smartweed	Polygonum spp.	Aug – Sep
Common Chickweed	Stellaria media	Apr – Jul			minor source
Germander	Teucrium chamaedrys	Jul – Aug
Alsike Clover	Trifolium hybridum		yellow brown		good source
Crimson Clover	Trifolium incarnatum		dark brown
White Clover	Trifolium repens	Jun – Jul	caledonian brown		good source
Cat-tail	Typha latifolia	Jun – Jul
Common vetch	Vicia cracca	Jul – Aug
Spring Vetch	Vicia sativa	Jul – Aug
Sweet Corn	Zea mays	Jun – Jul	yellowish white	cultivated

Fall

Flowers and annual crop plants – Fall

Common name	Latin name	Blooming months	Pollen color	Availability	Source for honeybees
Aster	Aster spp.	Sep-Frost	reddish yellow
Borage	Borago officinalis	Jun – Frost
Melons	Cucumis melo	Jun-Frost		cultivated
Sweet autumn clematis	Clematis ternifolia	late Sept	white	ornamental
Pumpkin	Cucurbita pepo	Jun-Frost	bright yellow	cultivated
Ivy	Hedera spp.	Sep – Oct	dull yellow or black?	feral and ornamental
Goldenrod	Solidago spp.	Sep – Oct	golden	feral

^{[5] [6] [7] [8] [9]}

See also

• Forage (honey bee)
• List of honey plants
• Melliferous flower
• Nectar source

Notes and References

1. http://www.nhb.org/download/research/rvalue.pdf THE R-VALUES OF HONEY: POLLEN COEFFICIENT
2. Reiter, R, THE COLORATION OF ANTHER AND CORBICULAR POLLEN, THE OHIO JOURNAL OF SCIENCE, VOL. XLVII JULY, 1947 No. 4, Camden, N. J.
3. https://kb.osu.edu/dspace/bitstream/1811/3589/1/V47N04_137.pdf
4. http://www.die-honigmacher.de/kurs2/pflanze_23.html?PHPSESSID=019c9dbb5abce89ffb53037d0187a4a2 Die Honig Macher
5. Bienenweide Arbeitsblatt 207, Bieneninstitut Kirchhain, 2001
6. Tew, James Some Ohio Nectar and Pollen Producing Plants Ohio State University Extension Fact Sheet, 2000
7. Stahlman, Dana Honey Plants Flowering Plants/Trees 2004
8. Hodges, Dorothy; The pollen loads of the honeybee, Bee Research Association Limited, London, 1952
9. Lamp, Thomas; Bienennährpflanzen 1 : Gehölze Nov 1999; accessed 05/2005