Showy Milkweed (Asclepias speciosa) for Butterflies
Asclepias speciosa is commonly known as Showy Milkweed and rightly so. The flowers look like an explosion of stars and are fragrant. Butterflies find them attractive for nectar and the Monarch caterpillars enjoy munching the leaves. It is a major host plant of the Monarch butterflies in the Western part of the US.
Growing Conditions of Asclepias speciosa
Showy milkweed is the “Western version” of Common Milkweed (Asclepias syriaca) and is native to all the Western states and Central states as well as into Canada. Common Milkweed is native in the East and Central US and the two overlap some in the Central states. Both are hardy in USDA zones 4-9.
Asclepias speciosa is a found in roadside ditches, fields, around fence posts, railroad tracks and other abandoned/distressed areas. It is, however, a very pretty and fragrant flowered milkweed with large fuzzy blue-green leaves.
Showy milkweed prefers full sun and will tolerate drought once the plant is established. It can be found in dry areas as well as mesic (medium moist) and will do fine in poor soils but needs good drainage. The mature plant height is about 4 ft (though this can vary widely with different conditions).
As an herbaceous perennial it will die back each fall to return in the spring. Showy milkweed will put on a flower show for several months from summer to fall.
Using Showy milkweed in the Butterfly Garden
Asclepias speciosa is a host plant for Monarch butterflies. Adult female butterflies are attracted to milkweeds on which they lay their eggs. The caterpillars must eat milkweed (many milkweed varieties are good for them) in order to grow and complete their transformation to a chrysalis then butterfly.
By planting milkweed your garden will become extra attractive to the Monarchs; however, Monarchs are not the only butterflies that may come to visit. It just so happens that many types of butterflies are attracted to milkweeds because they are a great nectar source. That is why milkweeds are some of the best plants for butterfly gardens!
However, Showy milkweed can be invasive in a garden setting. Like Common milkweed it will spread not only by seed but also by underground rhizomes. Some people have reported that Showy milkweed is a little less aggressive than Common milkweed but it still may be better suited for large areas or natural settings rather than an ornamental butterfly garden. You may want to consider some “better behaved” types of milkweed plants for small gardens
Asclepias speciosa from Seed, Propagation
Showy milkweed is easily grown from seed and can also be propagated through rhizome cuttings. The seeds can be sown outdoors in the fall or winter-sown.
Showy milkweed seeds need 30 days of cold stratification to improve germination,
Sow the seeds about 1/8 – 1/4 inch deep. Germination can occur as quickly as one week but may take longer.
Showy Milkweed seeds and plants for sale
Showy milkweed is a lovely plant if you have the space for it or the tolerance for its tendency to spread! Many have reported success growing it outside of its native region and it has also been reported to do well in large containers. Certainly this will add beautiful and fragrant flowers to your butterfly garden with a lot of leaves for your Monarch caterpillars!