Common Milkweed Seeds 6987 (Asclepias syriaca). Monarch butterflies (Danaus plexippus) only lay eggs on plants in the milkweed family. The Milkweed host-plants are the only food Monarch caterpillars eat. Milkweed is no longer listed as an Ontario noxious weed. Do not consume any part of a milkweed plant as the sap contains cardiac glycosides that are poisonous to humans and livestock, if ingested in significant quantities. Flowers are attractive, fragrant and extremely popular nectar and pollen sources for pollinators (bees in particular). Perennial hardy to Zone 3.
How to Grow
140 to 180 seed/gram. Naturally stratify seed by sowing directly outdoors in the fall in a sunny site – cover seed very lightly with soil. Indoors sow seed in a soil-less medium in early February, barely cover seed as diffuse light aids germination. Stratify seed by placing container in a refrigerator or other cold place for 3 months. Bring the container out and keep at 20 C (70 F) for the 10-18 day germination period. After germination grow on under lights at a slightly cooler temperature before hardening off and transplanting outside after the danger of frost has passed. Plants grow 60-120 cm (2-4′) tall. Seed from mature plants disperses easily by wind action. Common milkweed prefers full sun locations in well drained soil. Often found in fallow or abandoned fields, fence rows, roadsides and dry meadows.