According to observations of naturalists and beekeepers.
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Calendula (Calendula officinalis, Asteraceae) is one of the easiest herbs to grow and a highly versatile medicinal plant - naturally, it finds its way into the hearts and gardens of all herb lovers. They are native to southwestern Asia, western Europe, Macaronesia, and the Mediterranean.
Popular herbal and cosmetic products named 'calendula' invariably derive from C. Officinalis. Calendula species have been used traditionally as culinary and medicinal herbs. The petals are edible and can be used fresh in salads or dried and used to color cheese or as a replacement for saffron.
This plant is present in at least 15 states/provinces in this country.
Depending on variety and culture, the plants grow 30.5-76.2 cm in height and about as wide. The leaves are bright green and typically about 10.2 cm long. The lower leaves are oval with a rounded tip (spatulate) and upper leaves are lance-shaped with pointed tips.
The flowers are typically 5.1-7.6 cm in diameter and held on thick sturdy stems. Calendulas are single or double-flowered and come in a range of colors from cream to light yellow to electric yellow to orange. Some have dark brown centers and all are beautiful.
Regular pinching keeps the 30-90 cm plant bushy and prevents tall, spindly stalks.
If deadheaded regularly, this plant can bloom from spring through fall and beyond. In warmer areas, the calendula may take a break from blooming during summer heat and then put on a show as temperatures fall in autumn.
Acer saccharinum (aka: Silver maple, Soft maple)
Pyrus communis (aka: European pear, Common pear)
Celtis laevigata (aka: Hackberry, Sugarberry, Lowland hackberry, Sugar hackberry, Arizona sugarberry, Netleaf hackberry, Small's hackberry, Southern hackberry, Texas sugarberry)
Acer negundo (aka: Boxelder, Western boxelder, Arizona boxelder, California boxelder, Texas boxelder, Interior boxelder, Violet boxelder)
Rubus spectabilis (aka: Salmonberry)
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)
Salix exigua (aka: Narrowleaf willow, Coyote willow)
Prunus americana (aka: American plum, Goose plum, River plum, Wild plum)
Acer grandidentatum (aka: Bigtooth maple, Canyon maple, Western sugar maple)
Prunus cerasus (aka: Sour cherry, Tart cherry, Dwarf cherry, Montmorency cherry)
Crataegus douglasii (aka: Black hawthorn, Douglas hawthorn, River hawthorn, Western thornapple)
Populus tremuloides (aka: Quaking aspen, Trembling aspen, Aspen, American aspen, Mountain aspen, Golden aspen, Trembling poplar, White poplar, Popple, Alamo Blanco)
Salix scouleriana (aka: Scouler's willow, Upland willow)
Acer circinatum (aka: Vine maple)
Prunus emarginata (aka: Bitter cherry)
Malus fusca (aka: Oregon crab, Oregon crab apple, Pacific crab apple, Western crab apple)
Salix bebbiana (aka: Bebb willow, Beak willow, Beaked willow, Long-beaked willow, Diamond willow, Chaton, Petit Minou, Smooth Bebb willow)
Acer macrophyllum (aka: Bigleaf maple, Big-leaf maple, Oregon maple)
Malus domestica (aka: Pyrus pumila, Malus pumila, Apple)
Acer platanoides (aka: Norway maple)
Rubus ursinus (aka: California blackberry, California dewberry, California grapeleaf dewberry, Douglasberry, Pacific blackberry)
Salix drummondiana (aka: Drummond's willow, Beautiful willow, Blue willow)
Salix lemmonii (aka: Lemmon's willow, Lemmon willow)
Salix planifolia (aka: Diamondleaf willow, Planeleaf willow)
Salix boothii (aka: Booth's willow)
Salix amygdaloides (aka: Peachleaf willow, Peach leaf willow)
Robinia pseudoacacia (aka: Black locust, False acacia, Yellow locust, White locust, Green locust, Post locust, Falsa acacia, Robinia)
Ajuga reptans (aka: Bugle, Blue bugle, Bugleherb, Bugleweed, Carpetweed, Carpet bugleweed, Common bugle, St. Lawrence plant)
Astragalus (aka: Milkvetch, Locoweed, Goat's-thorn)
Rubus laciniatus (aka: Cutleaf blackberry, Evergreen blackberry, Slashed blackberry)
Rhus glabra (aka: Smooth sumac, Common sumac, Rocky Mountain sumac, Red sumac, Western sumac, White sumac)
Salix geyeriana (aka: Geyer willow, Silver willow)
Brassica napus (aka: Rapeseed)
Allium schoenoprasum (aka: Chives)
Sinapis arvensis (aka: Charlock mustard, California rape, Charlock, Corn mustard, Canola, Kaber mustard, Rapeseed mustard)
Prunus serotina (aka: Black cherry, Wild black cherry, Rum cherry, Mountain black cherry, Wild cherry)
Calendula officinalis (aka: Marigold, Calendula, Pot marigold, English marigold)
Prunus virginiana (aka: Chokecherry, Western chokecherry, Common chokecherry, Black chokecherry)
