The secret life of milkweed

Even its name classifies it as unwanted, but milkweed plays a crucial role in nature — and the average garden.

Most famous for its role in hosting butterfly caterpillars, milkweed is the only plant that can support the lovely orange and black monarch butterfly’s caterpillar. Late in the summer, you can lift up a milkweed leaf and see the fat caterpillars feasting on the foliage.

According to the North American Butterfly Association, the 25 varieties of milkweed protect themselves with poisonous steroids called cardenolides, related to the chemical that illuminates fireflies. The monarch, in particular, stores the poison in its wings, making it an unpleasant treat for birds.

But monarchs are hardly the only creature that relies on milkweed. The plain Jane white milkweed tiger moth produces a lovely caterpillar with orange and black stripes and a fancy skirt. The tiger moth lays a cache of dozens of eggs in neat rows on the milkweed, which all hatch at once.

In late summer, milkweed produces lots of little flowers in a round ball. These blooms emit a strong and lovely lavender fragrance that can perfume an entire garden. The flowers turn into large, pointed seed pods that eventually break open and spill little seeds that float away on their fluffy parachutes.

American pioneers would collect the seed pods and use them to decorate their homes. The gold-painted pods can still be seen on Christmas trees.