Gardening for butterflies is a suspenseful art, a bit like holding a picnic and wondering if your invited guests will show up. It's because butterflies are choosy insects. Any gardener can have aphids, but red admirals, painted ladies and tiger swallowtails insist upon certain amenities, such as sunshine and shelter from wind.
To butterflies, the plants in a garden are more important than the design. They need flowers for nectar throughout the growing season. Luckily, many common annuals and perennials are top-notch nectar flowers. While native American species play an important role as host plants for hungry butterfly caterpillars, most adult butterflies have cosmopolitan tastes, supping as readily on the nectar-filled flowers of exotic plants as natives.
Butterflies seem especially attracted to gardens boasting generous patches of a given nectar flower. If you plant Jupiter's-beard (Centranthus ruber), don't settle for one or two plants. Try growing three or more patches of this especially popular nectar flower, and watch the swallowtails drift from clump to clump.
Because I love old-fashioned cottage gardens, my garden is filled with informal groups of plants of varied heights, including many low growers spilling forth onto the garden's gravel paths.
Grape hyacinths, Pulmonaria, rock cress, azaleas, lilacs, wallflowers and pinks furnish nectar in early and mid-spring. From late spring on through autumn, many butterfly plants bloom. Primula vialii, the June-blooming orchid primrose, is thickly interplanted with tall forget-me-nots. I use perennial alpine pinks, biennial sweet William, and self-sowing annual candytuft to edge beds of Jupiter's-beard and June-blooming yarrows (Achillea) such as pale yellow 'Taygetea' and 'Moonshine'. I planted tall perennial phlox and purple coneflowers behind the Jupiter's-beard to provide color and nectar in July and August.
Joe-pye weed (Eupatorium purpureum) dominates one end of the garden. It waves its butterfly-laden flower heads for weeks in late summer. In front of it are patches of red bee balm (Monarda) and the tall hybrid yarrow, 'Coronation Gold'. A large drift of purple-flowered anise hyssop (Agastache foeniculum), completes the picture. Although the garden hosts a variety of nectar flowers, the butterflies concentrate when anise hyssop and Joe-pye weed bloom. Edging this bed are clumps of golden marjoram, oregano, rosy-flowered ice plant (Hylotelephium spectabile 'Carmen'), and the little Mexican daisy (Erigeron karvinskianus).
In arid regions use drought-tolerant butterfly flowers. Asters (Aster novi-belgii), butterfly weed (Asclepias tuberosa), Coreopsis, fleabane (Erigeron), Jupiter's-beard, Lantana, lavender, Sedum, verbena, and yarrow all thrive on dry, sunny sites.
If your garden has a low, damp area, plant moisture lovers like the rosy-flowered swamp milkweed (Asclepias incarnata), Joe-pye weed, forget-me-nots, bee balm, and meadow sweet (Filipendula palmata). Create a shallow puddle to attract swallowtails, blues, sulfurs and other butterflies that enjoy drinking at mud puddles. (They do so to obtain needed salts in their diet.) A sprinkling of table salt and the addition of some manure will increase the puddle's appeal for butterflies. Salt harms plants, however, so use a plastic liner or locate the puddle away from your flower border.
Butterfly gardeners should not use insecticides and herbicides. Many pesticides kill indiscriminately so doom butterflies or their larvae. My advice? Don't fret too much about caterpillars chewing your prized plants. Natural predators usually keep caterpillar populations under control. Also, the larvae of many butterflies feed only on certain plants and trees.
Mostly, I welcome the occasional presence of butterfly caterpillars in my garden, sometimes carrying one indoors along with a spray of its food plant so that I can observe the miracle of metamorphosis. West coast ladies sometimes lay eggs on the leaves of ornamental mallows. Painted ladies, which instinctively lay their eggs on thistle plants, also find an acceptable substitute in the hairy leaves of borage. Spying dozens of painted lady caterpillars on your borage plants does not mean the end result will be a crowd of butterflies emerging from their cocoons in your garden. Such collections of juicy caterpillar morsels are handy food marts for wasps and hungry birds.
Each delicately winged butterfly that graces your garden spent a part of its life in another, less well known form: a larva. To enjoy butterflies in greatest abundance, learn to recognize them whatever their stage of growth. All begin as an egg, which shortly becomes the larval form, a caterpillar. After feeding, caterpillars pupate in a chrysalis, then transform into beautiful butterflies.
(Papilio glaucus and P. rutulus) The caterpillar lives in a leaf shelter of its food plant, often trees such as cherry, poplar, birch, and basswood. The large adult is a common sight in gardens.
(Danaus plexippus) Birds learn fast to avoid this caterpillar and butterfly. The larvae absorb toxins from their food plant, milkweed.
(Junonia coenia) This caterpillar is gardener-friendly because it eats weeds such as plantain. The "eyespots" on both wings of the adult are used to frighten predators.
(Vanessa cardui) Colors on the caterpillar vary, but the yellow side stripes are consistent. Because the adults are so adaptable, this species is particularly widespread.
Great Spangled Fritillary
(Speyeria cybele) The butterfly's name comes from the silvery "spangles" visible on the undersides of wings. The favorite food plant of the spiny caterpillar? Violets.
(Vanessa atalanta) This caterpillar feeds on nettle plants, inside an individual leaf tied up with silk. Adults like to linger on sunny garden paths, and often rest on a wooden structure--or the gardener!
(Nymphalis antiopa) This spiny caterpillar feeds on nettles, elm, willow, poplar, and birch. Look for sunbathing adults on sunny, late-winter days, a sign that spring is near.
(Papilio polyxenes) Just about any plant of the carrot family, such as carrots, dill, and parsley, are fair game for this caterpillar. When you see the butterflies in your garden, you know the caterpillars will follow soon.
Alice Yarborough gardens and writes from her home in Carnation, Washington. This article was adapted from Butterfly Gardens, (Brooklyn Botanic Garden, Brooklyn, NY, 1995; $8).
Photography by Suzanne DeJohn/National Gardening Association
Article published on June 23, 2008.