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Asclepias Species, Narrow-Leaf Milkweed, Mexican Whorled Milkweed

Asclepias fascicularis

Family: Apocynaceae (a-pos-ih-NAY-see-ee) (Info)
Genus: Asclepias (ass-KLE-pee-us) (Info)
Species: fascicularis (fas-sik-yoo-LAIR-iss) (Info)
Synonym:Asclepias fasciculata
Synonym:Asclepias mexicana



Foliage Color:

Unknown - Tell us

Bloom Characteristics:

This plant is attractive to bees, butterflies and/or birds

Water Requirements:

Average Water Needs; Water regularly; do not overwater

Where to Grow:

Unknown - Tell us


24-36 in. (60-90 cm)

36-48 in. (90-120 cm)


18-24 in. (45-60 cm)

24-36 in. (60-90 cm)


USDA Zone 6a: to -23.3 C (-10 F)

USDA Zone 6b: to -20.5 C (-5 F)

USDA Zone 7a: to -17.7 C (0 F)

USDA Zone 7b: to -14.9 C (5 F)

USDA Zone 8a: to -12.2 C (10 F)

USDA Zone 8b: to -9.4 C (15 F)

USDA Zone 9a: to -6.6 C (20 F)

USDA Zone 9b: to -3.8 C (25 F)

USDA Zone 10a: to -1.1 C (30 F)

USDA Zone 10b: to 1.7 C (35 F)

Sun Exposure:

Full Sun


All parts of plant are poisonous if ingested

Bloom Color:

Pale Green

White/Near White

Bloom Time:

Mid Summer

Late Summer/Early Fall



Other details:

Unknown - Tell us

Soil pH requirements:

6.1 to 6.5 (mildly acidic)

6.6 to 7.5 (neutral)

7.6 to 7.8 (mildly alkaline)

7.9 to 8.5 (alkaline)

Patent Information:


Propagation Methods:

From seed; direct sow outdoors in fall

Seed Collecting:

Bag seedheads to capture ripening seed

Allow pods to dry on plant; break open to collect seeds


This plant has been said to grow in the following regions:

Evening Shade, Arkansas

Agoura Hills, California

Brentwood, California

Laguna Beach, California

Long Beach, California

Los Angeles, California

Malibu, California

Perris, California

Richmond, California

San Marcos, California

Stockton, California

Tracy, California

Gold Hill, Oregon

Portland, Oregon

Kerrville, Texas

show all

Gardeners' Notes:


On Jun 17, 2013, montsho from Tracy, CA (Zone 9b) wrote:

This plant grows under some extreme conditions and seems to like sun, heat, drought and high wind. It grows at the edge of open fields near the road in my area. It is easy to kill with too much water so water regularly for about a week or 2 to get settled then leave it alone!


On Sep 9, 2011, TnWren from Evening Shade, AR (Zone 7a) wrote:

It is a native wildflower here in the foothills of the Ozarks and I am glad to have it for the butterflies and bees who enjoy it.
It's growing in rocky, acidic soil in partilal shade and appears to be very drought and heat tolerant.
It doesn't appear to be invasive here and I plan on harvesting more seed this year and planting it out around the property.


On Nov 11, 2008, CBernard from Perris, CA (Zone 9a) wrote:

I have been growing this asclepias for three years now. It does spread quite rapidly. However, that is no problem when you consider how many butterfly species that the larva feed on this plant (besides Monarchs). It depends on what your objectives are.


On Jul 18, 2008, Ficurinia from Portland, OR wrote:

I bought this plant a few years ago and it is only just beginning to bloom this year. Planted in the drought-tolerant area in my garden, its leaves blend in well with the other plants, and the blooms are amazing.


On Jun 14, 2006, Scorpioangel from Gold Hill, OR (Zone 7a) wrote:

This roadside 'weed' is invasive and very hard to get rid of once a stand is started. The only plus for this plant is the fact that it is food for Monarch's.