Narrowleaf Milkweed Seeds for Monarch Butterflies

Asclepias fascicularis is commonly known as Narrowleaf milkweed or Mexican whorled milkweed and is a common host plant for Monarch butterflies in the Western US. This is one of the many milkweeds on which the female Monarchs will lay their eggs so the baby caterpillars can eat and grow.

Mexican whorled milkweed is also used by adult butterflies and other insects because the flowers are an excellent nectar source. Doubling as a nectar and host plant is common for many milkweeds and this one is no exception.

Characteristics of Asclepias fascicularis

Narrowleaf milkweed creates small patches by spreading through underground rhizomes but is not as aggressive as some other milkweeds.

The rhizomes also make this a very drought tolerant plant.  They are often found in areas that receive moisture through winter/spring months and are dry in the summer.  However, it is reported that these milkweeds do quite well in a variety of soils and moisture conditions.

Full sun is preferred as with most milkweeds and will bring about the best flowering but the plant will grow in part shade.  The flowers are white with a tint of lavender, are fragrant, and are seen from late spring through summer.

The leaves are narrow and grow in a whorled pattern on stems that reach from 2-3′ tall.  More stems will be produced each year.  This milkweed is hardy in zones 6-10 and is an herbaceous perennial.

Starting Narrowleaf Milkweed Seeds

Narrowleaf milkweed seeds germinated easily for us with no cold stratification or other pre-treatment needed. We just planted them about 1/8-1/4″ deep at room temperature and kept them moist.  Germination occurred withing a couple weeks.  These seeds can be fall planted, started indoors before the last frost, or started outdoors in the spring.

Narrowleaf Milkweed is great choice for an Easy, Native, Western butterfly garden to feed the Monarchs!