Mexican Whorled Milkweed

Asclepias fascicularis

Taxonomy

Division:
Magnoliophyta | - Flowering plants
Family:
Apocynaceae
Genus:
Asclepias
Species:
Asclepias fascicularis

Growth Characteristics

Life Cycle:
Perennial
Growth Habit:
Forb/herb
Height:
3-4 ft
Light Requirements:
Full Sun
Drought Tolerance:
High
Bloom Months:
jun, jul, aug, sep
Bloom Colors:
White, Pink, Green, Purple

Native Range

United States: California, Idaho, Nevada, Oregon, Utah, Washington

Keystone Species Ranking

Caterpillar Keystone:
★★★★☆ Based on number of butterfly and moth species using this genus as host plant (Source: National Wildlife Federation)

Host Plant for Caterpillars

Clio Tiger Moth (Ectypia clio), ⚠️Monarch butterfly (Danaus plexippus), Queen butterfly (Danaus gilippus)

Reported Fauna Sightings

Bees: Black-tailed bumble bee (Bombus melanopygus), Black-tailed bumble bee (Bombus melanopygus), Brown-belted bumble bee (Bombus griseocollis), Brown-belted bumble bee (Bombus griseocollis), Crotch bumble bee (Bombus crotchii), Crotch bumble bee (Bombus crotchii), Fernald cuckoo bumble bee (Bombus flavidus), Fernald cuckoo bumble bee (Bombus flavidus), Fuzzy-horned bumble bee (Bombus mixtus), Fuzzy-horned bumble bee (Bombus mixtus), Indiscriminate cuckoo bumble bee (Bombus insularis), Indiscriminate cuckoo bumble bee (Bombus insularis), Morrison bumble bee (Bombus morrisoni), Morrison bumble bee (Bombus morrisoni), Nevada bumble bee (Bombus nevadensis), Nevada bumble bee (Bombus nevadensis), Sitka bumble bee (Bombus sitkensis), Sitka bumble bee (Bombus sitkensis), Two-form bumble bee (Bombus bifarius), Two-form bumble bee (Bombus bifarius), Western bumble bee (Bombus occidentalis), Western bumble bee (Bombus occidentalis), Yellow head bumble bee (Bombus flavifrons), Yellow head bumble bee (Bombus flavifrons), Yellow-faced bumble bee (Bombus vosnesenskii), Yellow-faced bumble bee (Bombus vosnesenskii)

Soil Requirements

Soil Type:
well-drained, sandy or loamy soil
pH:
6.0 - 8.0 (slightly acidic to neutral)
Drainage:
excellent drainage required
Moisture:
dry to moderate
Notes:
Thrives in open, sunny areas; often found in grasslands and open woodlands.

Germination Information

Pre-treatment: Seeds are placed in fine mesh bags into a 1% hydrogen peroxide (3:1 water/3% hydrogen peroxide) soak for 24 hours, rinsed, and placed in water for an additional 24 hours. The bags are placed in sealed containers in refrigeration at 1 to 3 °C for 45 days. Check seeds weekly for mold and treat with 1% hydrogen peroxide if necessary.

Establishment: There are some variations in the protocols. Protocol 1 does not require any pre-treatment and germination takes 6-8 weeks, while Protocol 2 suggests a hydrogen peroxide treatment and germination takes 10-14 days. Collect seeds after pods have ripened, but before they have split open. The seeds are wind dispersed, so be careful when gathering to place in a paper or burlap bag to avoid losing them.

Source: npn.rngr.net