Butterfly Basics

A butterfly garden needs to provide two kinds of food:

  • host plants for caterpillars
  • and nectar sources for adult butterflies.
20120729-132636.jpg A butterfly-friendly garden in Prospect Park, Brooklyn

Nectar Sources

Finding nectar sources is probably the easiest part of planning a butterfly garden.  Many well-loved flowers such as phlox, sedum, lilac, mums, butterfly bush, and coneflower are excellent choices and are available at most local garden and hardware stores.  To feed butterfiles year-round, select plants that extend your blooming season over many months. For instance, lilacs bloom in the spring, while butterfly bush, phlox and coneflower bloom in summer, and sedum and chrysanthemums peak in the fall.

Even the average urban gardener has almost limitless options in this area.  As you shop, keep in mind that diversity, an extended bloom season, and inclusion of native species are important goals.

Caterpillar Host Plants

Ultimately, butterfly gardening goes beyond planting pretty flowers.  The next step is to look for plants (usually natives) that can serve as hosts for caterpillars.  Many species, such as the Monarch butterfly, have evolved to eat certain plants as larvae.  Unfortunately, the populations of these host plants has diminished as urban and rural development has increased.  Some of North America’s most beloved butterflies are now in decline – but putting a few host plants in your garden can help. If you can fit a butterfly milkweed on your balcony garden, you can be part of the solution!

Milkweed

Milkweed is a genus of plants that are named for the milky juice they excrete when broken. They also contain toxic chemicals that Monarch caterpillars ingest to make themselves unappetizing to predators.

Three main species of Milkweed are commonly grown in gardens for their flowers and their non-aggressive tendencies.

  • Butterfly Milkweed (Asclepias tuberosa)
  • Swamp Milkweed (Asclepias incarnata)
  • Tropical Milkweed (Asclepias curassavica)

Two of them (A. tuberosa and A. incarnata) are perennials here in Brooklyn. Tropical milkweed must be replanted every spring.

Tropical milkweed (Asclepias curassavica) growing in an 8th Street tree box. Balloonplant (Asclepias physocarpa) is an African native that has naturalized in many parts of the world. Here it is growing the Brooklyn Botanical Garden.

There are many other milkweed species that are suitable Monarch hosts. Smaller vendors are more likely to have a wide variety of rare species, though Butterfly Milkweed and Swamp Milkweed are often available at local stores. One of the most incredible lists of milkweed I’ve seen is from Georgia Vines, a small nursery that offers about 50 different species and cultivars. Prairie Moon Nursery is also a great source for seeds, especially if you choose to grow plants that are native to the US.

Other Host Plants

A comprehensive list of larvae host plants can be found at The Butterfly Site.  To get started, considered some of these plants.

  • Violets (if your yard is like mine, Mother Nature will provide plenty of these whether you want them or not!)
  • Pipevine
  • False Indigo
  • Lupine
  • Passion flower
  • Hops
  • Mallows & Rose Mallows
  • Hollyhocks

Tolerate a Little Chaos

Raising little caterpillars in your green space sounds really adorable and, arguably, bad-ass.  After you get all your host and nectar plants in the ground and successfully defend them against disease and weather, you’re going to feel proud of yourself and get attached to your pretty flowers.

Just keep in mind that when the caterpillars finally arrive, they’re going to be tiny destructive forces in your garden – ie., they’re going to be eating your flowers (time and money).

That’s ok.  Those caterpillars might grow up pollinate your vegetable garden one day.

Sources and Further Reading

The North American Butterfly Association

Monarch Watch

Asclepias, from Wikipedia, the free encyclopedia