What do plants for butterflies have to do with supporting birds? Several things:

  • Remember Doug Tallamy’s estimate that it takes 6,000 to 9,000 caterpillars to raise one brood of chickadees? Well, sad to say from the butterflies’ perspective, but butterfly (and moth) larvae = caterpillars = great baby bird food. (In fact, I read somewhere that a reason butterfly numbers increase in July and August is because most songbirds are done raising their young so the predation pressure on caterpillars is less.) By providing good butterfly habitat, you’ll be feeding birds as well as supporting butterfly populations.
  • Some birds eat adult butterflies, too! Warblers, orioles, Blue Jays, flycatchers, and others will catch the adults and chow down. Some birds (presumably those that glean from leaves) will also eat butterfly eggs. OK, again, not so nice for the butterflies, but that’s the way nature works. Everything eats something, and in a healthy system, butterflies reproduce at a rate that lets enough survive to mature and make the next generation. Also, birds sometimes take just a bite out of a butterfly wing, and the butterfly can survive that.
  • Good butterfly habitat is also useful bird habitat more generally, since it requires a diversity of native plants (and, ideally, a water source). Plants full of native flowers are plants with lots of insects (not limited to butterflies), which is great for birds.
  • The fluffy hairs attached to milkweed seeds that help them float to new locations are used by some birds to line their nests, and the fiber of milkweed stems is sometimes used in building nests.
Great Spangled Fritillary and Delaware Skipper on Common Milkweed

Great Spangled Fritillary and Delaware Skipper Butterflies on Common Milkweed

Butterfly Weed in Garden Setting

Butterfly Plants

Adult butterflies need plants that provide nectar, but it is also critical for them to have the right plants to lay their eggs on. Plants evolve chemical or other defenses (such as spines or hairs) to keep from being over-consumed, and butterfly species have evolved alongside them. Each species of butterfly is usually specialized through evolution so that their caterpillars can defeat the defenses of a particular group of plants. If the right plants aren’t available, there is no next generation. So, not just any old plant, even if native, works.

Milkweeds are for Monarchs – and More

Milkweed flowers are good sources of nectar for butterflies, but their importance is far greater. Monarch caterpillars have evolved to be able to handle the toxin in milkweeds, and they require plants in this family to grow on. Without milkweeds, there will be no monarchs.

That by itself is reason enough to plant milkweed. But the nectar is also attractive to many other insects, providing a bounty of food for insect-eating birds. Other types of butterflies and bees, moths, flies, and beetles are among the insects attracted to milkweed flowers.

Milkweeds are Not Weeds

Did you know that “weed” is not a botanical category? A weed is just any plant that is somewhere you don’t want it. Whoever gave milkweeds their English name obviously didn’t want them. Probably they were popping up in ornamental gardens of prized exotics. But just because someone in an earlier era didn’t want them doesn’t mean we shouldn’t! Milkweeds have beautiful flowers and are essential for healthy ecosystems.

Milkweed Species for Pennsylvania

Swamp Milkweed

Common Milkweed. Common milkweed is a tall, sturdy plant with a beautiful, fragrant ball-like cluster of pink flowers. It is extremely attractive to pollinators, and its wide leaves provide lots of food for monarch caterpillars. It grows readily in sunny areas in varied soils. It does spread vigorously through the roots and can be hard to discourage once the roots get established. Common milkweed is beautiful and important but is usually best for larger properties.

Swamp Milkweed. Swamp milkweed has a pretty pink flower cluster (less ball-like than common). It is not as tall or wide-leaved as common milkweed. It will reseed itself but not aggressively and does not spread through the roots, so it works better in smaller spaces. It likes sun or part sun. It does not require a swamp, contrary to its name, as long as the soil is not too dry. Average garden soil should be fine.

Butterfly Weed

Butterfly Weed. Milkweed also comes in orange! Butterfly weed produces profuse bright orange-yellow clusters of flowers that are stunning in combination with other flower colors such as blue. It is the shortest of the three, growing to only about 2 or 3 feet. It forms a clump that eventually can take on the shape of a small shrub. It prefers soil that is not too rich or too moist. It is slow to come up in the spring, so if you plant one and fear it has not survived the winter, just keep waiting! Usually they begin to emerge after most of your other plants have.

Tropical Milkweed – NOT. No, no, no. Don’t buy or grow this one. It is sometimes sold around here but it is not native to PA and is problematic. According to the Xerces Society, it can harbor a protozoan parasite that attacks monarchs. Also, by blooming late into the season, it can trigger breeding at the wrong time. And it may reseed and begin to take over areas where it is not wanted. For more information, visit the Xerces Society webpage (a great source of information on supporting butterflies and other insects, including other pollinators.)

To Note. The toxin in milkweeds should not be consumed by grazers such as goats, cows, and horses. If you pasture domestic animals in a field, keep milkweed out of it. And keep pets away from areas with milkweed if they are prone to chewing plants.

Barbara Malt, Vice President of the Lehigh Valley Audubon Society and PA Master Naturalist, author and all plant photo credit

Butterflies on Common Milkweed image with permission from Karen Campbell.