"Milkweed is named for its milky juice which consists of a latex containing alkaloids and several other complex compounds including cardenolides. Some species are known to be toxic.
Asclepias species produce their seeds in follicles. The seeds, which are arranged in overlapping rows, have white silky filament-like hairs known as pappus, silk, or floss. The follicles ripen and split open and the seeds, each carried by several dried pappus, are blown by the wind. They have many different flower colorations.
Milkweeds are an important nectar source for bees and other nectar-seeking insects, and a larval food source for monarch butterflies and their relatives, as well as a variety of other herbivorous insects (including numerous beetles, moths, and true bugs) specialized to feed on the plants despite their chemical defenses.
Milkweeds use three primary defenses to limit damage caused by caterpillars: hairs on the leaves, cardenolide toxins, and latex fluids. Data from a DNA study indicate more recently evolved milkweed species use less of these preventative strategies, but grow faster than older species, potentially regrowing faster than caterpillars can consume them.
Milkweed is beneficial to nearby plants, repelling some pests, especially wireworms.
Being the sole food source of monarch butterfly larvae, the plant is often used in butterfly gardening.
In a garden, milkweed flowers will produce a strong and beautiful fragrance that will be as powerful as in any other flower."
Taken from wikipedia's page at:
http://en.wikipedia.org/wiki/A...
