When fully grown, Asclepias asperula can reach up to 2 feet in height and has an upright, sprawling growth habit. The plant's stems are densely covered with tiny hairs and feature narrow, irregularly grouped leaves 4-8 inches long. The large, thick, narrow leaves often fold lengthwise, resembling the horns of an antelope, hence the plant's vernacular name "antelope horn."

The caterpillars of Monarch butterfly species feed on milkweed plants, including the antelope horn.

Antelope horn plants produce attractive, robust flower heads, and their common name is derived from the curved shape of the seed pods. It is common for aphids to be found on antelope horn plants. Although only a problem if the plant appears unhealthy, aphids can be effectively managed by spraying the plant and aphids with soapy water or high-pressure water while supporting the plant with your hand.

In addition to being toxic to animals, including humans, like many others in the genus Asclepias, this plant contains harmful substances. Some people may be sensitive to the sap of these plants, and a person's sensitivity to the toxin can depend on factors such as age, weight, health condition, and susceptibility. Children are the most vulnerable due to their curious nature and small size. A plant's toxicity can vary depending on the season, parts, and growth stage. Furthermore, plants can absorb toxic substances from the air, water, and soil, such as herbicides, pesticides, and pollutants.