The Main Plant entry for Milkweeds (Asclepias)

"The Milkweed plant contains a chemical called cardenolides. This chemical is a form of a steroid and is a cardiac arrester (stops the heart). Different species of Milkweed have differing concentrations of this chemical. When a Monarch caterpillar eats the leaves from the Milkweed plant it ingests the cardenolides which then makes it toxic to many vertebrate predators. For example, if a bird ate a Monarch butterfly or caterpillar it would throw up. Research has found that Monarchs that have high levels of cardenolides (from having eaten those Milkweed plants with higher concentrations of the chemical) are much less susceptible to being predated by birds and mice! Isn't this a great way to keep the 'bad guys' away?" (My Monarch Guide.com)

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"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...

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I do like both the white-flowered and the pink-flowered types of milkweed. Both are pretty and I grow both in my garden. The butterflies don't seem to be choosy. They also like both. Bees and butterflies both visit the flowers when they are in bloom, but Milkweed is the host plant for the Monarch Butterfly.

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