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Milkweed Plants


Picture of common milkweed flowers.

Picture of Asclepias syriaca flowers.

David Beaulieu

Taxonomy of Milkweed Plants:

Plant taxonomy classifies common milkweed plants as Asclepias syriaca.

Plant Type:

Milkweed plants are herbaceous perennials.


Common milkweed plants are tall (3 feet), thin, summer-bloomers. The flower cluster forms a globe atop the plant's rigid stem. The flowers come in various shades of pink, and they are fragrant flowers. Leaves are broad-oblong and light green. Seed pods that resemble small cucumbers succeed the flowers. The pods in turn burst open in late summer to early fall, exposing their seeds. The seeds are attached to white silky hairs, meaning the slightest wind will distribute them. Click on the "More Images" link under the picture above for a photo of the pod.

Planting Zones for Milkweed Plants:

Milkweed plants grow as wildflowers in fields and along roadsides in Eastern North America. The common type typically grows in zones 3-9.

Sun and Soil Requirements:

Common milkweed plants grow best in full sun and in a well-drained soil. Like many types of wildflowers, Asclepias syriaca is a drought-resistant plant.

Uses for Milkweed Plants in the Landscape:

Famed as a plant that attracts butterflies, this wildflower is a must-have for the butterfly garden. It is the host for monarch butterfly caterpillars. Monarch butterflies deposit their eggs on milkweed plants; once the caterpillars emerge, they eat the leaves.

Others grow it specifically for wildflower gardens. Yet another use for it involves the seed pods: they can be dried and used in crafts.


There's no need to fertilize milkweed plants, as they tolerate poor soils. Your biggest maintenance challenge with them will probably be in containing them. Asclepias syriaca spreads both via seeds and rhizomes, forming colonies.

At the very least, you may wish to remove the seed pods before they open. Otherwise, they will spread to distant corners of your yard (and beyond), thanks to the silky appendages that allow the seeds to waft on the slightest breeze. They are rather like the seeds of dandelions in this regard.

Caveats in Growing Milkweed Plants:

While some parts of Asclepias syriaca served culinary and medicinal purposes for the native population, this wildflower's status as a poisonous plant warrants mention, since its leaves are toxic. Never ingest wild foods until you have first consulted with experts (I am not an expert in this area).

Unless children or pets will be in your yard, a more serious drawback to growing it may be its proclivity to spread aggressively (see above in the "Care" section).

Other Types of Milkweed Plants:

Many find butterfly weed (Asclepias tuberosa), with its bright orange flowers, a more attractive type of milkweed than the common milkweed. Another type of milkweed is swamp milkweed (Asclepias incarnata).

Fun Facts About Milkweed Plants:

The genus name, Asclepias derives from the name of the Greek god of medicine, Asclepius; it refers to its medicinal uses. The specific epithet, syriaca, may, however, be a misnomer, according to Gaertner and others: from most of what I've read on the subject, Asclepias syriaca appears to be indigenous to North America, not to Syria.

Upon any damage to the stem or leaves, a white, milk-like substance oozes out, which gives the weed its common name.

As mentioned above, the leaves are poisonous, and the monarch butterfly caterpillars treat these leaves as a food source. While they, themselves do not die from eating them, the toxins make the caterpillars poisonous to predators -- a nice trick!

Consult my resources on plants that attract butterflies to learn more about creating both butterfly gardens and wild bird havens.

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