Monarch larvae appear to feed exclusively on milkweeds in the genus Asclepias and several other genera of viny milkweeds in North America. Milkweeds are perennial plants, which means an individual plant lives for more than one year, growing each spring from rootstock and seeds rather than seeds alone. In the Midwest, milkweeds were historically common and widespread on prairies, but habitat destruction has reduced their range and numbers.
Milkweeds belong to the family Asclepiadaceae, derived from Asklepios, the Greek god of medicine and healing. Though most members of the genus Asclepias are tropical, there are approximately 110 species in North America known for their milky sap or latex contained in the leaves. Most species are toxic to vertebrate herbivores if ingested due to the cardenolide alkaloids contained in the leaves and stems. When Monarch larvae ingest milkweed, they also ingest the plants’ toxins, called cardiac glycosides. They sequester these compounds in their wings and exoskeletons, making the larvae and adults toxic to many potential predators. Vertebrate predators may avoid Monarchs because they learn that the larvae and adults taste bad and/or make them vomit. There is considerable variation in the amount of toxins in different species of plants. Some northern species of milkweed contain almost no toxins while others seem to contain so much of the toxins that they are lethal even to monarch caterpillars.
Asclepias curassavica – Tropical Milkweed
Tropical Milkweed, also known as Blood flower, is a tender evergreen perennial in the dogbane and milkweed family. It is native to South America, but has naturalized worldwide in many tropical and subtropical areas. It has a much longer flowering period than the perennial milkweeds that are winter hardy in Michigan. Showy red-orange flowers bloom late spring through late autumn except in USDA Zones 9-11 where it is winter hardy. Grows best in light, rich, evenly moist, well-drained soil in full sun. Will tolerate light shade and some soil dryness. Hummingbirds, butterflies and bees are attracted to the flowers. Monarch butterflies lay eggs on this plant and the resulting larvae (caterpillars) use the plant leaves as a food source. Flowers are followed by long, narrow seed pods (3-4” long) which split open when ripe releasing silky tailed seeds for dispersal by wind. Stems and leaves exude a milky sap when cut or bruised. Plants can be poisonous to livestock. Consider wearing gloves when working with these plants because the milky sap is poisonous if ingested and can be toxic to human skin.
Asclepias hirtella – Tall Green Milkweed
Asclepias hirtella Tall Green Milkweed is a Michigan native although it is considered threatened in the state. Tall Green Milkweed is found throughout the Tallgrass Prairie region in open areas, usually in prairies or remnants of prairies and throughout the midwest. Though not as well known as other varieties of milkweed, Tall Green Milkweed distinguishes itself with abundant clusters of green-white flowers that attract many butterflies and bees.
Other Common Names in use include Green Milkweed.
Available May 2017
Asclepias incarnata – Ice Ballet Milkweed
‘Ice Ballet’ is an elegant, long-blooming, bright white cultivar of native Asclepias incarnata (Swamp Milkweed) and features a compact habit and dark green foliage. Swamp milkweed occurs throughout most of the United States. It is a tall plant found in moist habitats such as wet meadows, floodplains, riverbanks, pond shores, stream banks, wet woods, swamps, and marshes, although it will also grow in drier areas such as prairies, fields, and roadsides. Asclepias incarnata needs full sun or partial shade to flourish. Flowers are very attractive to butterflies and bees as a nectar source. Swamp milkweed is also an important food source for the larval stage of Monarch butterflies. The plants are deer resistant and heat tolerant.
Available – May 2017
Asclepias perennis – Aquatic Milkweed
Aquatic Milkweed is a petite white milkweed suitable for wet soils. It survives in water and will grow in light-sandy and medium-loamy soils. Native to stream sides it is generally most common in lightly shaded woodlands near streams. This little milkweed is a great performer, being shade tolerant and flowering spring through autumn.
Available to ship mid-late June.
Asclepias purpurascens – Purple Milkweed
DISTRIBUTION
USA: AR, CT, DC, DE, GA, IA, IL, IN, KS, KY, LA, MA, MD, MI, MN, MO, MS, NC, NE, NH, NJ, NY, OH, OK, PA, RI, SD, TN, TX, VA, WI, WV
Asclepias purpurascens – Purple Milkweed is a Michigan native milkweed and is native to most of the eastern United States though it is uncommon to rare in cultivated gardens. Similar to Ascelpeias syriaca (Common Milkweed) it is an excellent garden choice due to its non-invasive nature. It has a long bloom season and the fragrant, intense rosy pink flowers attract numerous insects and butterflies. Purple Milkweed is very tolerant of a wide variety of soils and light levels making it easy to grow. It will tolerate shade, but blooms better in the sun. It commonly occurs in dry to moist open woods, dry ridge tops, thickets, glades, prairie openings, stream banks and wet meadows.
All of our plants are grown without the use of harmful pesticides and are safe for developing larvae.
Grown in 4.5″ square pot.
Available mid-late June 2017
Asclepias sullivantii – Sullivant’s Milkweed / Prairie Milkweed
Winner of the 2015 Green Thumb Award for Best New Product!
Also known as Prairie Milkweed, Sullivant’s Milkweed is a long-lived perennial and a well-behaved relative of Common Milkweed. Very similar in appearance, it is less aggressive and an excellent choice for butterfly gardens. Prairie Milkweed grows best in a sunny, medium to medium-moist garden. The pinkish, mauve flowers are very fragrant and attract hummingbirds, bees, and butterflies. Sullivant’s Milkweed is listed as ‘threatened’ in Minnesota, Wisconsin, Michigan.
Available – May 2017