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Common Milkweed

An entry level native plant that most people will recognize, Common Milkweed, Asclepias syriaca, is heralded for its support of the well-known Monarch Butterfly. Milkweeds are the only plants that Monarchs will lay eggs on and the only one that the caterpillars will feed on. A shortage of milkweeds is credited for the decline of Monarch populations in recent decades. Experts estimate that at least a billion new Milkweed plants are needed across North America to stop the decline in Monarch populations. This is an achievable goal if we provide the seed and plants to anyone with a small patch of ground to plant them in.

Common Milkweed is a medium tall plant (3-5 ft.) with large oval leaves and spherical inflorescences about the size of tennis balls. The pink to lavender flowers bloom for several weeks in high summer. It is known for its sticky white sap (milk) that is toxic to most animals except the Monarch. The seed pod is a tapered follicle about 3-4 inches long that matures in early fall. When mature it splits open to expel a hundred or more disc-like seeds that ride the air waves on fuzzy white threads. The scientific name, Asclepias, comes from the Greek God of medicine who is often seen holding the caduceus, a serpent entwined staff still used today as a symbol for physicians. However, medicinal uses for members of this genus are suspect. The species name, syriaca, was likely a misunderstanding of its origin. The plant is from North America, not the middle east.

It grows easily in full sun and in all but the wettest of soils. It is fond of disturbed sites like railroad embankments, old fields, and abandoned properties. It tends to establish colonies by root sprouts and may be aggressive in gardens where it can fill in every available niche when unattended. Milkweed gained notoriety during the second world war when its floss (the fuzzy white threads) was harvested for use in life preservers. It is still used as filler in pillows and comforters.

Plants can be propagated by division in early spring or by seed. Sowing directly is the most strait forward method starting plants from seed. Scatter seeds on the soil about a half inch apart and cover lightly with a quarter inch of soil. Water frequently and be patient as germination may take several weeks. For spring sowing, it is best when seeds are cold stratified. This can be done by keeping seeds in a refrigerator or un-heated garage over the winter.

Direct sowing where they will grow takes some patience. A year or two may pass before you get results. Seeds need only be covered by the thinnest layer of soil. Turn your leaf rake upside down and tickle the soil enough to make good seed/soil contact. A light cover of straw may be helpful. Fall/winter sowing is often successful.

Starting seeds indoors is preferred by many since it avoids hazards such as weather extremes and pests. Plants should grow for up to two months or when they reach 5-6 inches height. Transplant out 6-24 inches apart.

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