According to observations of naturalists and beekeepers.
Where are you?
Sinapis arvensis, the charlock mustard, field mustard, wild mustard, or charlock, is an annual or winter annual plant of the genus Sinapis in the family Brassicaceae.
Sinapis arvensis is an aggressive weed that is native throughout most of the temperate regions of Europe, Asia minor, southwest Asia, and North Africa. It has become naturalized throughout much of North America and is a highly invasive species.
This plant is present in at least 62 states/provinces in this country.
Sinapis arvensis reaches on average 20–80 centimeters of height, but under optimal conditions can exceed one meter. The stems are erect, branched, and striated, with coarse spreading hairs especially near the base. The leaves are petiolate (stalked) with a length of 1–4 centimeters. The basal leaves are oblong, oval, lanceolate, lyrate, pinnatifid to dentate, 4–18 centimeters long, 2–5 centimeters wide. The cauline leaves are much reduced and are short petiolate to sessile but not auriculate-clasping.
The inflorescence is a raceme made up of yellow flowers having four petals. The fruit is a silique 3–5 cm long with a beak 1–2 cm long that is flattened-quadrangular.
It blooms from May to October in North America, or May to August, in the UK. The species is hermaphrodite (has both male and female organs) and is pollinated by Bees, flies.
Brassica napus (aka: Rapeseed)
Allium schoenoprasum (aka: Chives)
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)
Calendula officinalis (aka: Marigold, Calendula, Pot marigold, English marigold)
Cucumis sativus (aka: Cucumber, Cetriolo, Gherkin)
Chamaenerion angustifolium (aka: Fireweed, Great willowherb, Rosebay willowherb, Saint Anthony's Laurel, French-willow)
Agastache foeniculum (aka: Giant hyssop, Blue giant hyssop, Anise hyssop, Fragrant giant hyssop, Lavender giant hyssop)
Borago officinalis (aka: Borage, Starflower, Common borage, Cool-tankard, Tailwort)
Cucumis melo (aka: Cantaloupe, Rockmelon, Sweet melon, Spanspek, Honeydew melon, Honeymelon, Crenshaw, Casaba)
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)
Hyssopus officinalis (aka: Hyssop)
Asteraceae (aka: Aster, Daisy, Composite)