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Friday, June 24, 2016

Flower Friday: There's a "whorled" of beauty in whorled milkweed.

Whorled milkweed (Asclepias verticillata)
Click on terms for botanical definitions.

Whorled milkweed showing slight color variation in corollas.
Narrow, grass-like leaves are also visible.
Photos by Eleanor Dietrich.
Whorled milkweed is an herbaceous perennial wildflower. It is one of the smaller, more delicate native milkweeds. Flowers
are born in umbels in groups of 15-20. The corolla is reflexed and white to greenish-white with tips that may be tinged in reddish-purple. Leaves are long, linear and sessile with margins that are entire and revolute. Leaves are arranged in whorls around the stem (hence the common name). When not in bloom, whorled milkweed is easily overlooked as its narrow leaves blend in with grasses. Seeds are ovately flat with many fine, silky hairs attached to their apices that aid in dispersal.  They are born in erect follicles that are narrow and smooth.

Like all milkweeds, whorled milkweed is a larval host plant for the monarch butterfly and is attractive to a variety of pollinators. It flowers late spring through late summer/early fall.

The species name verticillata refers to the verticillate (i.e. whorled) arrangement of the leaves.

Family: Apocynaceae (Dogbane family)
Native range: Nearly throughout
To see where natural populations of whorled milkweed have been vouchered, visit www.florida.plantatlas.usf.edu/Plant.aspx?id=3470.
Hardiness: Zones 8a-10b
Soil: Moderately moist to moderately dry, sandy to calcareous soils
Exposure: Full sun to minimal shade
Growth habit: 1-3’ tall
Propagation: Seeds
Garden tips: Whorled milkweed may be used in a moist wildflower garden. It may need to be reseeded periodically to maintain a population.

Caution: Whorled milkweed is considered the most toxic of all milkweeds, specifically to livestock, and as such should not be planted where cattle are known to forage.


Whorled milkweed is occasionally available from nurseries that specialize in Florida native plants. Growers may post availability on www.plantrealflorida.org.