Commonly known as milkweed, Asclepias is a genus of herbaceous, perennial, flowering plants in the Apocynaceae (dogbane) plant family. Named for Asclepius, the Greek god of healing, plants exude a sticky, milky substance where cells are damaged. They are found throughout North and South America with over 100 species native to the United States, with several cultivated as flowering ornamentals. The National Garden Bureau has designated 2025 as The Year of the Asclepias in an attempt to encourage gardeners to plant this attractive and useful flowering perennial which is vital to the survival of the monarch butterfly.

Species of the genius Asclepias serve as the sole food source for larvae of the monarch butterfly. Simply put, without Asclepias there would be no monarchs. (Credit: National Garden Bureau)

Both animals and humans use milkweed for many different purposes. Monarch butterflies rely exclusively on milkweed plants as a food source for their larvae. In short, without milkweeds there would be no monarch butterflies. Native Americans used stem fibers of milkweed to make string, rope, and cloth. Additionally, some tribes used common milkweed (Asclepias syriaca) for medicinal purposes, such as using the milky sap to treat warts, ringworm, and bee stings.

Hollow and coated with wax, the seed fibers (floss) of asclepias are quite buoyant. In nature, this helps with seed dispersal. During World War II, more than two million pounds of asclepias seed floss were used to fill life preservers and other flotation equipment.

Because of their buoyant nature, seed floss of Asclepias was used during World War II to fill life preservers. (Credit: University of Illinois)

An interesting aspect of Asclepias is the many different species from which to choose. All have a variety of benefits that add value to a garden. Spending time learning about the different options is the best way to identify and select the right milkweed to grow in one’s landscape.

Although more than 100 species of Asclepias exist, listed below are five of the more popular and interesting ones:

1. A. asperula ssp. capricornu (Antelope Horns) – Antelope horns is a milkweed common to the Southwest. It grows as a clump one to two feet in height with an upright or sprawling habit. Its stems are densely covered with minute hairs. The leaves are four to eight inches long, narrow, and irregularly grouped. The long, thick, narrow leaves are often folded lengthwise. As its green seed follicles grow in length and begin to curve, they are said to resemble antelope horns, giving rise to its common name.
   
   

   Antelope horns (Credit: National Garden Bureau)

2. A. incarnata (Swamp Milkweed) – Swamp milkweed features vibrant pink blooms that attract pollinators, including monarch butterflies and native bees. As its name suggests, it thrives in wetter conditions and clay or mucky soil, making it ideal for rain gardens and wetlands. This milkweed grows up to four feet in height and blooms from June to October. Its flowers are generally light pink to light purple in color.
   
   

   Swamp milkweed (Credit: National Garden Bureau)

3. A. speciosa (Showy Milkweed) – A beautiful, manageable alternative to common milkweed (Asclepias syriaca), showy milkweed features large, velvety oval-shaped leaves and clusters of fragrant, flowers that provide essential nectar for butterflies, bees, and hummingbirds. It grows about four feet tall and produces rose, pink-, and purple-colored flowers. Tolerant of many soil types, it needs a full sun exposure.
   
   

   Showy milkweed (Credit: National Garden Bureau)

4. A. syriaca (Common Milkweed) – Common milkweed is a deciduous, native, herbaceous perennial wildflower. It grows in average, well-drained soils in full sun but can tolerate poor or dry soils. It propagates easily by seed or root cuttings and will naturalize in the garden, taking up quite a bit of space. In summer, five-petaled flowers bloom with up to 100 flowers per cluster and one to three clusters per stem. Fragrant flowers in colors of green, pink, white, and purple or lavender normally last from June through August. Plants grow between three and five feet in height and thrive in dry, sunny areas.
   
   

   Common milkweed (Credit: USDA)

5. A. tuberosa (Butterfly Milkweed) – This stunning native milkweed features clusters of vibrant yellow to bright orange flowers, providing a splash of color that attracts monarchs, queen butterflies, and a host of other pollinators. With its compact, shrub-like structure, butterfly milkweed is perfect for urban or suburban yards and even large containers. Plants grow about three feet tall and prefer sandy, loamy, or rocky limestone soils.
   
   

   Butterfly milkweed (Credit: National Garden Bureau)

While milkweeds can be beautiful and beneficial, some can be harmful to some animals and humans. For example, Tropical Milkweed (Asclepias curassavica) can play host to a protozoan parasite that reduces body mass, lifespan, mating success, and flight ability of monarchs. Unfortunately, this attractive plant disrupts the butterfly’s instincts to mate, migrate, or overwinter.

A little research on which species to add to your garden will go a long way in assuring its success. Typical gardening considerations like water, sun, height, spacing, bloom time, or color considerations will continue to apply for milkweeds. Additional things to consider when deciding which Asclepias is right for you include:

• Species’ growth habit – Because many milkweed species grow quite quickly, know which is best for your area to help prevent them from taking over your garden or nearby plants.
• Native status – Species that are native to your area are the typically preferred milkweeds, however, introduced species that are nonthreatening to native plants or ecosystems can coexist with the native plants. Know the status of the species for your region to prevent the expansion of harmful invasive species.
• Companion plants – Many different types of ornamental companions can be planted alongside milkweeds to maximize esthetic impact. Grasses can add beauty to a meadow scape as can additional flowers that provide nectar for adult monarchs and other butterflies.

Milkweeds can be started in the garden in a variety of ways including from seeds, dormant roots, or live plants. They are low-maintenance perennials that have an extended bloom time. To optimize the likelihood of monarch butterfly visitation, plant at least five individual plants in an area, when possible.

Acknowledgement: Adapted from an article by the National Garden Bureau