Photo copyright © 2018 Mariposa Native Plants
A native perennial herb, with white, cream, or lavender flower clusters and long, narrow pointed leaves, these often whorled about the long stems. The plant emerges late in the spring and thrives throughout the hot summer, relying upon its deep root system. It produces slender, curved seed pods later in the summer. These break open to disperse seeds attached to white, fluffy fibers that catch the wind and propagate the plant. A.fascicularis is winter deciduous. The most important thing: This plant is a primary host for the monarch butterfly caterpillar.
Photo copyright © 2018 Mariposa Native Plants
Photo copyright © 2018 Mariposa Native Plants
A close-up of A.fascicularis in the early fall, with its seed pods opening. Note the fluffy fibers that help the wind propel the seeds away from the site. This plant will continue to turn brown, dry up, and wither as the fall progresses. There will be just a few dry stalks sticking up throughout the winter. In the late spring, however, shoots will begin to emerge from the ground around the plant, and it will grow back even larger than in the previous year.
A.fascicularis is found in diverse environments--mountains, valleys, foothills, arroyos, dry and wet areas, roadsides, railroad right-of-ways--across California and the western U.S. Elevation: sea level to 10,000 ft. (3000m). Sun: full or partial. Temperature: cold tolerant to 5°F (-15°C). Soil: clay, sandy, or saline; pH 6-8.
Easy to care for once established. Needs a site that is well-drained. Roots are sensitive to disturbance; avoid breaking the root ball when planting from the container. Water (.5 gallon, 2 liters) once per week until the first winter. Water once per month, same amounts, in the second summer. Thereafter, no supplemental water required. A.fascicularis can become weedy (this is good! for the monarch butterfly); plan your site accordingly.
A.fascicularis is the primary host plant for the monarch butterfly's caterpillars. Milkweeds, and A.fascicularis among them, contain within them an alkaloid that is mildly poisonous and distasteful to birds and other predators. However, the monarch has adapted to this biological quirk, and the caterpillars feed on the milkweed leaves and fine stems, absorbing the alklaoid, which renders them quite unpalatable to predators.
Aphids: Young plants especially are subject to aphids. Brush the aphids off gently by hand, with a soft brush, or with a spray of water from the garden hose. Please do not use pesticides on A.fascicularis, because these chemicals harm the monarch butterfly caterpillars. California native plants are adapted to withstand the insect pests, and they really don't need chemical help from you to do so. Also, the aphids are a prime food target for the helpful lady beetle insect, so leaving a few of them on the plant confirms an established food and life cycle.
Gophers: Might eat at the roots of A.fascicularis as a last resort.
Deer: Do not seem to browse on narrow leaf milkweed.
Although not particularly beautiful to the aesthetically-inclined native plant gardener, this plant is becoming more popular as its crucial role in supporting and preserving the monarch butterfly in the western U.S. becomes more widely recognized.
Mariposa ecotype, #1 container, about 1 gallon
Central Valley ecotype, #1 container, about 1 gallon
Seeds for either of the above ecotypes, 25 seeds/packet