Butterfly Garden Plants
Green Antelopehorn Milkweed flower
Green Antelopehorn Milkweed flower, photographed by Don DuBois.

Asclepias viridis, listed as Green Antelopehorn by the USDA Plants Database, is also called spider milkweed by many sources. But a search of the USDA Plants Database listing for spider milkweed turns up a different milkweed, Asclepias asperula.

WIth at least 110 species of milkweed in the United States, it is not always an easy job to figure out which milkweeds are which. In the case of sorting out A. viridis and A. asperula, it is helpful to look at the native distribution ranges for both plants. A. viridis has a native range of Texas north to Nebraska and eastward as far as West Virginia and South Carolina. Asclepias asperula has a native range from Texas north to Nebraska and Idaho and extending westward to California.

Both species of milkweed are loved by Monarchs. In Texas, Asclepias viridis is quite common and is considered an important food source for the Monarchs as they start their spring migration northward.

Importance as a butterfly nectar source:
Although only a few caterpillars use milkweed as caterpillar food, the nectar provided by milkweeds is relished by a wide variety of butterflies including swallowtails, whites, checkerspots to name just a few.

Importance as a caterpillar food source:
Green Antelopehorn is used by Monarchs, Queens, and Soldiers as a caterpillar food source. In certain parts of Texas, Green Antelopehorn is very important to Monarchs as move northward from Mexico in the spring.


Cultural Requirements

USDA Hardiness Zone4 to 9
Bloom PeriodApril to July
Bloom ColorGreen
Plant Height1 to 3 feet
Plant SpreadVaries
Light ExposureFull sun
Soil MoistureMedium to dry
Animal/Disease ProblemsNone
Asclepias viridis

Native Range


Plant Rating
Plant rating scale ranges from 0 to 3. Plants rating 3 are the most useful for butterfly gardens. For more details on the ratings, see Native Plant Ratings

Garden Rating2
Nectar Rating3
Caterpillar Rating3