Asclepias oenotheroides

Asclepias oenotheroides, (Sidecluster Milkweed, Zizotes Milkweed)

General Description

The flower of this species is unique among milkweeds. The long, slender hoods extend beyond the stigmatic groove and flare or bow outward at the top. This species survives periodic droughts and occasional mowing even though it has shallow roots. It leafs out and flowers if rains follow a dry period. Plants tend to be scattered and populations appear to have a low density. One of the least conspicuous milkweeds.

Also known as zizotes from “hierba de zizotes”, the Spanish common name for this plant. This species was sometimes used by Native Americans to make a poultice for skin rashes.


Distribution: CO, LA, NM, OK, TX

Flower: Green with a purple tinges. Erect umbels, one to several per stem with 15 +/- flowers per umbel. Corolla reflexes backwards.  Horns protrude through the hoods.  Corolla is a lighter shade of green compared to the hoods.

Foliage: Stands erect, one to a few stems. Leaf arrangement is opposite or sub-opposite. Leaf attachment is petiolate with ½ -1 in (1-2 ½ cm) long petioles.

Growth Period: Spring

Habitat: Grows in sandy, rocky ground conditions, prairies, ditches and fields.

Height: 12-18 in (30 ½ – 46 cm).

Leaves: Ovate, 1-4 in (2 ½ – 10 cm) long and ½ -2 ½ in (1-6 cm) wide. Wavy edges.

Root: Taproot.

Toxicity: Medium. Sap is rumored to cause skin irritation but this “fact” requires verification.


Blossoming Season: March – September.

Life span: NA

Propagation: From seed.

Pods: Often grow in pairs, length up to 3 ½ in (9 cm) by 1 ½  in (4 cm) wide.

Seed Color: Brown.

Environment and Growth Requirements

Maintenance: Low

Overhead Conditions: Sunlight required. Shade intolerant.

Precipitation: 10-30 in (25-76 cm) annually.

Soil Texture: Grows in course, medium, or fine soils.

Temperature: Can tolerate a minimum temperature of –10 to 0 Fahrenheit (-23 to -18 Celsius).

Work Cited:,,,, Plants of Deep South Texas: A Field Guide to the Woody and Flowering Species

Photos: Bobby Gendron