Plant of the Week: Common milkweed

The High Line's planting design is inspired by the self-seeded landscape that grew up between rail tracks after the trains stopped running in the 1980s. Today, the High Line includes more than 500 species of perennials, grasses, shrubs, and trees – each chosen for their hardiness, adaptability, diversity, and seasonal variation in color and texture. Some of the species that originally grew on the High Line's rail bed are reflected in the park landscape today. This week we share one of our gardeners' current favorites with you.

Photo by Ayinde Listhrop.

Many people enjoy gardens for the wildlife they attract and for the plants themselves. When a plant attracts animals like hummingbirds, bees or butterflies, it provides even more visual interest and ecological value to the garden. Common milkweed (Asclepias syriaca), which can be found in bloom on the High Line this week, is an excellent example of a plant that has many benefits to the environment. It is well loved by many pollinators, in particular the increasingly endangered monarch butterfly.

The monarch lays its eggs on milkweed species and the caterpillars feed exclusively on these plants. As more native prairie land is lost to agriculture and housing, the habitat for milkweed is being destroyed. One small thing gardens can do to help butterflies is to plant varieties of milkweed, including butterfly milkweed (Asclepias tuberosa), purple milkweed (Asclelpias purpurascens), or common milkweed (Asclepias syriaca), all of which can be found in the park.

Photo by Ayinde Listhrop.
Asclepias syriaca is native to all Eastern and Midwestern states, excluding Florida. Populations also exist in Montana and Oregon. It is a vigorous perennial that grows up to 6.5 feet high and has striking pink flowers. It has opposite leaves, a hairy stem, and can also be identified by the milky sap that gives the genus its common name. In the winter, the plant can be recognized by the familiar seedpods that characterize the family. On the High Line, Asclepias syriaca has self-seeded in the Interim Walkway in the northern section of the park. It spreads through both seed and underground rhizomes, and in the wild, it often forms extensive colonies. Some home gardeners avoid Asclepias syriaca because it can become an aggressive spreader.

The milkweed's genus, Asclepias, is named for the Greek god of medicine, Asklepios. The plant's milky sap was often used in folk remedies. However, all parts of the plant are poisonous including the sap, so this is not recommended. The plant is known to be extremely deer resistant for the same reason. Monarch caterpillars are one of the few creatures who can consume milkweed without being harmed, and it provides the additional benefit of making the caterpillars and butterflies poisonous to predators. In addition to monarchs, common milkweed is also a favorite pollen source for swallowtail and queen butterflies, bumblebees, hummingbirds, honey bees, moths and many others. During World War II, milkweed was grown over large areas to produce fiber for rope, and the ultra-soft seeds were used to stuff pillows.

PLANTING TIP

Asclepias syriaca can be an excellent addition to a home garden, but since it spreads rapidly, it may be a good idea to plant in a container to prevent this. The plant also needs full sun. Aphids can be a problem with all milkweed species—if the problem is severe, the aphids can be sprayed off with the hose while watering. Be sure to lightly hold the plant in one hand while spraying so you can remove the insects without damaging the plant.

WHERE TO SEE THIS PLANT

Pershing Square Beams (West 30th St. between 11th and 12th Avenue) and Interim Walkway (Between 30th St. and 11th Avenue and West 34th St.)

Our horticultural team counts on members and friends like you to help keep the High Line beautiful and thriving. Join our community of supporters who play an essential role in the High Line's most important gardening projects.

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