This tough and widespread shrub, growing to 3' tall, is an important host plant for monarch butterflies. It has white to cream-colored flowers, sometimes with a tinge of purple. The attractive blue-gray leaves are hairy with a noticeable midvein, and the fruits are fat, tapering to a blunt tip. This species is widely distributed throughout the state, except in montane regions. It's found in dry rocky areas and also along stream banks. I first collected it near Gorman, California.
The native milkweeds are famous for being a host plant for the monarch butterfly. The butterfly lays its eggs on milkweed plants and only on milkweed plants, which supply the nutrients the egg needs as it turns into a caterpillar. Research on the reasons trend towards monarch extinction always lists the absence of only native as a major factor in successful monarch reproduction. Can be seen in summer covered with the green caterpillars that will become monarch butterflies. It grows 2-4' tall in full sun and can handle some shade. Do not plant non-native milkweeds; they can be a serious problem.
There are 75-100 seeds per packet, enough for at least 25 to 35 plants. Milkweeds need cold-stratification, which simulates cold weather. Place seed on damp paper towel. Put the towel and the seed in a plastic bag and place in a refrigerator. This is "cold-stratification." After a month, sow the seeds in a warm greenhouse. The seeds will appreciate some warmth to germinate. It goes dormant in the late summer. It spreads through underground rhizomes.
We recommend using species that grow in your region, if possible. Coastal gardeners should think twice before planting milkweeds, which may not have grown there historically. It may create problems to draw migratory species out of their regular patterns. For example, some species may not have resistance to the fungi stimulated by fog. The caterpillars that will develop on that plant may not survive, thereby "wasting" the eggs of that species.
Give them full sun and only water occasionally once they are established.These plants go dormant in late summer and fall. They spread through rhizomes into large clumps, and make a beautiful display.
It is hard to resist slitting the fat fruits along the seam with a fingernail, to watch the flat brown seeds with their feathery attachments float through the air. Planting milkweed in gardens away from the coast, where monarchs can find them, is highly recommended. Though monarchs may overwinter along the coast, they breed inland, and it is here that restoring milkweed can be most effective. This plant may go dormant in colder gardens.
Indian Milkweed is grown as part of a program initiated by the Xerces Society, whose goal is to protect waning Monarch butterfly populations. The demise of inland populations of milkweed, which are necessary to Monarch reproduction, are a big part of the problem. Widespread use of herbicides is another. Go to www.xerces.org/milkweed/ for more information.
There are 75-100 seeds per packet, enough for 20 to 30 plants.