Welcome to my zone 9a habitat garden near Houston, Texas.

Friday, April 22, 2011

Earth Day 2011: Asclepius and Asclepias

In ancient Greek religion, Asclepius was the god of medicine and healing. He represented the healing aspect of the medical arts and he had five daughters who were goddesses of five of those arts: Hygieia (Hygiene), Iaso (Medicine), Aceso (Healing), Aglaea (Healthy Glow), and Panacea (Universal Remedy). These names have come down to us through history and philology and we still honor them in today's language.

We don't know whether there was ever a historical Asclepius, although some historians speculate that there was and that the mythological character is based on him. Whatever the truth of the matter, the mythological character was and is well-known to students of the classics, of which Carl Linnaeus was one.

You may remember Linnaeus from your high school biology class. He is sometimes referred to as the "Father of Taxonomy" because he was the genius who came up with the system for giving scientific names to plants and animals. His system has stood the test of 300 years time and is still in use today.

When Linnaeus was casting about for a name for the milkweed genus, he was aware that these plants have many uses in folk medicine, and so what better source for a name for them than a derivative of the name of the ancient god of medicine? Thus the milkweed became Asclepias.

There are over 140 known species in the genus, Asclepias, but the one that is most often grown in our gardens is A. curassavica or tropical milkweed.

One of the tropical milkweeds blooming in my garden this spring.

The native milkweed that I grew up seeing around our yard and along roadways and in fields was a bushy plant with bright orange flowers. This is A. tuberosa. I have a couple of those in my garden, but they don't really grow as well here as the tropical milkweed does. They were slow to return after winter and are now about 3-4 inches high but are a long way from blooming.

The major interest of gardeners in milkweed today is not for its folk medicinal qualities but for its value to butterflies. Milkweed is well-known as the host plant for some species of much-loved and highly desirable butterflies, namely the Monarch and the Queen.

Hungry Monarch caterpillars munch their way through a tropical milkweed plant. Even if the plant loses all its leaves to the caterpillars, it will come back and grow new leaves.

The Queen caterpillar likes milkweed equally as well as the Monarch and, as you can see, looks very similar, except that it has a third set of antennae in the middle of its body.

Here, in shadow, you can discern that third set even more clearly.

Habitat gardeners, and, indeed, just about all gardeners, love butterflies and so we happily plant the host plants that we know they need to nurture and develop their caterpillars, even though we realize those plants are going to be eaten up. A raggedy looking milkweed plant in a perennial border is a sign of success to a gardener. (Wish I could claim that about some of my other raggedy looking plants!)

As Monarchs, as well as other butterflies, have suffered setbacks in recent years because of natural events and human-caused catastrophes, gardeners throughout the country have responded by planting more and more milkweed. By now, there is a well-defined trail that Monarchs can follow through gardens right across North America, from the mountains of Mexico to the plains of Canada.

On this Earth Day 2011, I celebrate all those gardeners who care enough to plant milkweed, even though it may not be the prettiest plant in the garden and it may go through its life with leaves full of holes. It is a plant that lives up to the root of its name - a god of medicine and healing. It has the capacity to help heal the environment and to heal the gardener's spirit as we happily watch those caterpillars destroying our plants and know the beauty that is to come.

Queen butterfly on milkweed.

The Monarch.


  1. Thanks, Celestial Elf. I'll give the film a look.

  2. Thanks for posting this. My tropical milkweed died in last winter's blast and I need to plant more. LOVED your caterpillar pictures!

  3. I was surprised that all my milkweed made it through the winter, Kathleen. I think it was probably down to the microclimate in which they were planted and the heavy mulch. I'm just glad they made it. I did buy a couple of pots from the nursery this spring though before my old plants got big enough to help the butterflies.

  4. great shots. i have lots of milkweed happening in my little garden, and can't wait for some caterpillars. i would be grateful just to see some eggs! lucky you!

  5. I bought one mildweed from Home Depot--found a caterpillar but the plant was drying from lack of water--raced to HD bought 3 more--soon I had 20 caterpillars and those babies can eat a smallish plant in a day! It has been a race to keep a continuing parade of caterpillars small and larger (and getting bigger each day) well fed. I discourage planting just one plant unless you are willing to 1) get more plants or 2) take them to a place where there is LOTS of milkweed. Just stop laying those eggs and migrate--will you!

  6. Each year I plant more varieties of milkweed. I find the plants interesting and the small blooms beautiful. We have climbing milkweed plus white and orange milkweeds that are native. I have planted at least four other varieties. So far the swamp milkweed has firmly taken root.