According to observations of naturalists and beekeepers.
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Field mustard is an upright winter annual or biennial that is a member of the mustard family (Brassicaceae). The oil made from the seed is sometimes also called canola or colza, which is one reason why it is sometimes confused with rapeseed oil.
This species is native to Eurasia, but has spread all over the world and is now naturalized throughout much of North America.
This plant is present in at least 63 states/provinces in this country.
Plants exist as basal rosettes until flowering stems develop at maturity, usually in the second year. Plants grow 1 to 3 (or 4) ft tall from a sometimes fleshy, enlarged taproot, with a many-branched stem. The foliage is generally hairless and sometimes covered with a whitish film. Lower leaves can reach 12 inches long, have a large central lobe, and usually one to four pairs of smaller side lobes. Upper leaves are smaller, non-lobed, and have a pointed tip and widened, clasping base. The bright yellow flowers are clustered at stem tops and have four petals that are 1/4 to 1/2 inch long.
Plants flower from June to August, depending on climate and latitude, and are insect-pollinated and self-incompatible.
Cercis orbiculata (aka: California redbud, Western redbud, Arizona redbud, Judas tree, Cercis occidentalis)
Acer negundo (aka: Boxelder, Western boxelder, Arizona boxelder, California boxelder, Texas boxelder, Interior boxelder, Violet boxelder)
Celtis laevigata (aka: Hackberry, Sugarberry, Lowland hackberry, Sugar hackberry, Arizona sugarberry, Netleaf hackberry, Small's hackberry, Southern hackberry, Texas sugarberry)
Acer glabrum (aka: Rocky Mountain maple, Douglas maple, Greene's maple, New Mexico maple, Torrey maple)
Salix lucida (aka: Shining willow, Greenleaf willow, Tail-leaf willow, Whiplash willow, Pacific willow, Lance-leaf willow, Longleaf willow, Red willow, Western shining willow)
Malus domestica (aka: Pyrus pumila, Malus pumila, Apple)
Acer grandidentatum (aka: Bigtooth maple, Canyon maple, Western sugar maple)
Crataegus douglasii (aka: Black hawthorn, Douglas hawthorn, River hawthorn, Western thornapple)
Salix exigua (aka: Narrowleaf willow, Coyote willow)
Populus tremuloides (aka: Quaking aspen, Trembling aspen, Aspen, American aspen, Mountain aspen, Golden aspen, Trembling poplar, White poplar, Popple, Alamo Blanco)
Salix lutea (aka: Yellow willow)
Salix scouleriana (aka: Scouler's willow, Upland willow)
Prunus emarginata (aka: Bitter cherry)
Prunus andersonii (aka: Desert peach, Desert peachbush, Anderson peachbush, Wild almond)
Salix bebbiana (aka: Bebb willow, Beak willow, Beaked willow, Long-beaked willow, Diamond willow, Chaton, Petit Minou, Smooth Bebb willow)
Salix drummondiana (aka: Drummond's willow, Beautiful willow, Blue willow)
Astragalus (aka: Milkvetch, Locoweed, Goat's-thorn)
Salix boothii (aka: Booth's willow)
Salix lemmonii (aka: Lemmon's willow, Lemmon willow)
Robinia pseudoacacia (aka: Black locust, False acacia, Yellow locust, White locust, Green locust, Post locust, Falsa acacia, Robinia)
Salix amygdaloides (aka: Peachleaf willow, Peach leaf willow)
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)
Rhus glabra (aka: Smooth sumac, Common sumac, Rocky Mountain sumac, Red sumac, Western sumac, White sumac)
Brassica napus (aka: Rapeseed)
Allium schoenoprasum (aka: Chives)
Sinapis arvensis (aka: Charlock mustard, California rape, Charlock, Corn mustard, Canola, Kaber mustard, Rapeseed mustard)
Gleditsia triacanthos (aka: Honey locust, Honey shucks locust, Common honeylocust, Sweet bean locust)
Prunus virginiana (aka: Chokecherry, Western chokecherry, Common chokecherry, Black chokecherry)
