Habit: rhizomatous perennial producing tall, upright stalks with narrow linear leaves 6 in (15cm) long either in whorls or oppositely placed around the rigid stem. If the plant is broken or pierced an alkaloid rich milky sap will flow freely. The inflorescence is an umbel (cluster of short flower stalks) made up of purplish pink to greenish white flowers. The fruits are smooth milkweed pods, which split open to release the seeds along with silky hairs. Blooms early summer to early fall.
Ecology: found in a variety of plant communities, near streams, from northeast Washington, south into Mexico from sea level to 7000 ft (2100 m).
Growing Conditions: full sun with well drained moist to dry soil. Tolerates clay and seasonal flooding.
Attracts bees and butterflies, most favored plant of Monarchs butterflies in California. Narrow-leaved milkweed is poisonous if ingested. Can spread rapidly through rhizomes and should either be maintained regularly or planted somewhere where this is desirable.