"Kids can rally around these vibrant, ephemeral creatures," explains Collegeville, PA, teacher Sandy Sweeney. "And by creating habitats for butterflies, students inadvertently invite and come to appreciate a whole range of other important (though less charming) organisms," she adds. What's more, butterfly gardens can provide an engaging centerpiece for exploring life cycles, habitat components, adaptations, and plant/animal interactions, and for exploring the implications of human-influenced habitat loss. And it can be as simple a project as a few containers of butterfly-nourishing plants on the windowsill, or as ambitious as a native wildflower meadow.
Before jumping in, it helps to understand what butterflies need at different life stages. The cycle begins when a butterfly lays its eggs on a "host" plant. Some butterflies will only lay their eggs on a single type of plant (e.g., monarchs on milkweed), while others have several choices. In five to ten days, the egg hatches and the tiny caterpillar eats the host plant, shedding its skin four to six times as it grows in size and weight. After two to four weeks, it attaches itself to a twig or other object and transforms into a pupa or chrysalis. This lasts about ten to 14 days, unless a butterfly species overwinters in this stage (different species overwinter in different life stages). During this time, major changes take place "behind the scenes." When the "metamorphosis," or change of form, is complete, an adult butterfly emerges.
Adult butterflies feed on nectar from flowers (inadvertently transferring pollen as they do so). During their 20- to 40-day life span, females search for specific plants on which to lay their eggs, and the cycle begins again. (Some, like monarchs, overwinter as adults and may live up to six months.) Most butterflies have two generations a year in the North, and more in the South.
Designing Your Butterfly Garden
Before researching butterflies and their needs, invite your students to do some sleuthing. Investigate the school grounds and neighborhood to discover what types of plants seem to attract butterflies. Can you find any butterflies laying eggs? Then have students check with Internet resources and local nurseries or Master Gardeners about butterflies likely to frequent your area, and the plants they prefer. Follow these cardinal rules of butterfly gardening, and you should be able to create an alluring site that nurtures and nourishes:
Include host plants for the butterfly "kids." The plants upon which butterfly larvae dine are typically weeds, wildflowers, shrubs, or trees native to the area. Some species will lay eggs on only one type of host plant, while others are less picky. Monarchs, for instance, are mad about milkweed. Other good larvae plants include white clover, hollyhock, stinging nettle, butterfly bush, and spicebush. Although many people regard butterflies as good, the site of a caterpillar devouring foliage might raise a pest patrol alert. Butterfly caterpillars do eat foliage, but most (except the cabbage butterfly) are not garden pests. Never use pesticides -- even organic ones -- in a butterfly garden, or you'll destroy your intended guests!
Choose a smorgasbord of nectar plants. These are plants with nectar-producing flowers that nourish mature butterflies. Most butterflies are attracted to a variety of brightly colored, sweet-smelling, simple flowers with accessible nectar. Flat flowers with "landing pads," like cosmos, or plants with lots of small flowers, like butterfly bush, are favorites. Others, like lupine, have short tubes leading to easy-to-find nectaries. And while color isn't everything, many butterflies seem to have a real passion for purples and pinks. Some preferred, easy-to-grow nectar plants are butterfly weed, lantana, butterfly bush, black-eyed Susan, purple coneflower, perennial aster, Joe-pye weed, cosmos, and zinnia.
Try to choose host and nectar plants that are native to the area. Since they evolved under local conditions and in step with the butterflies, native plants are better able to meet the creatures' needs. And because native plants are well adapted to your climate, soil conditions, and so on, they should also be easier to care for.
Keep the blooms coming. Remember, butterflies will have a number of generations per year, so be sure to choose plants with staggered bloom times to provide nectar throughout the season.
Consider the sun. Place the garden in a sunny area. Butterflies prefer nectar from sun-loving plants. Also include dark, flat stones. These will absorb the sun's heat and provide a warm spot where adults can bask, dry their wings, and warm their bodies for flying.
Use large splashes of color. Butterflies will hone in on bold clumps of colorful flowers. Keep a number of plants with similar flower colors together.
Provide puddles. Make sure your garden features puddles or other shallow water sources. In many species, males will congregate in "drinking clubs" (most likely to obtain salts and amino acids they require). If you have no naturally occurring puddles, try sinking a shallow container filled with moist sand or stones into the ground.
Never use pesticides. Even organic pesticides can harm caterpillars and butterflies.
Cultivate keen observers. The best way to learn about butterfly needs and preferences is to observe them carefully and take note of which plants and conditions entice your visitors.
Obtaining Butterfly Garden Plants
Once you have a plan for your butterfly- or bird-friendly garden and a list of plants that will do well in your area, you have several options.
* You can raise many butterfly nectar plants and some host plants in your indoor classroom garden, then transplant them outside in the spring. Marigolds, zinnias, parsley, dill, cosmos, sunflowers, black-eyed Susans, hollyhocks, and nicotiana are easy to start indoors.
* Approach parents, garden clubs, and local nurseries for donations of plants and divisions for your project. Personal letters from students describing the habitat project may elicit donations and reinforce communications lessons. Nursery people may even be willing to offer advice and guidance on planning, planting, and maintaining the garden.
* Consider saving and planting seeds from wild plants that attract butterflies.
Are Natives Friendlier?
A plant that is considered native to an area has evolved in a region over time and developed complex, interdependent relationships with other organisms. Some plants, for instance, depend on nutrients made available by certain types of local soil fungus. Certain butterflies depend for protection on toxic substances produced by local plants.
Consider planting or preserving as many native plants as possible in your schoolyard. Native plants are better designed to meet regional wildlife needs and, because they're adapted to local climatic conditions and soils, should be easier to maintain. Always try to obtain native plants from local or regional sources, or start your own from collected seeds of plants that are plentiful. Never dig up wild plants unless you're rescuing them from a site that's under construction.