Growing Green: The Butterfly Effect
Butterflies have long fascinated people with their beautiful wings and whimsical flight.
They are also extremely important ecologically. Butterflies pollinate flowering plants and serve as food for other organisms, thus forming an important link in the food chain.
Populations have declined in recent decades because of pesticide use, especially herbicides, loss of fence rows, urbanization, and other destruction of habitat, and loss of caterpillar host and nectar plants. Managing your garden for butterflies can help conserve butterfly populations as well as greatly enhance a traditional garden.
The life of a butterfly is marked by four vastly different stages: egg, caterpillar, pupa, and adult. The egg hatches into a caterpillar, which immediately feeds on the leaf of the plant where it has hatched.
Rapid growth is the main objective of the caterpillar stage. The caterpillar grows and molts, shredding its exoskeleton when it becomes too small. After four to six molts, the caterpillar pupates, or transforms.
The new stage is termed the pupa, and the covering around the caterpillar is called a chrysalis (or cocoon for moths).
Adult butterflies of most species emerge from the chrysalis after 10 to 15 days. They unfold and dry their wings, which must harden before they can fly.
Butterflies feed on nectar, the sweet liquid in flowers. Adults mate during this stage. The female deposits her eggs on plants that will provide food for the emerging caterpillars.
Because butterflies are attracted to flowers, it is easy to plant a garden that both you and they can enjoy. A butterfly-friendly garden contains both adult nectar plants and caterpillar host plants. A few common vegetables also serve as caterpillar host plants. Many butterfly gardeners plant extra vegetables, enough for them and their caterpillars. As an added bonus, butterfly gardens often attract hummingbirds.
Since butterflies are cold-blooded and need to be warm to fly and feed, plant your garden in a sunny area sheltered from the wind. Storms and high winds can damage butterfly wings, so be sure to provide a windscreen.
Choose the appropriate host and nectar plants to attract butterflies common to the Lehigh Valley. This includes hollyhock, dill, snapdragons, milkweeds, asters, dogwoods, butterfly weed, cosmos, Joe Pye weed, sunflowers, phlox, marigold, and zinnia.
Adult butterflies are more flexible in their need for nectar plants. In general, they prefer purple, red, yellow, orange, or pink blossoms; flat-topped or clustered flowers, and short flower tubes. A well-planned butterfly garden has blooming flowers throughout spring, summer, and early autumn. This provides a continuous food source to accommodate butterflies.
Butterflies are more attracted to groupings of flowers than to a single plant with a few blooms. Many cultivated flowers have been selected for their appearance, not their fragrance or the amount of nectar they contain. Therefore, it is better to choose common varieties for butterfly gardens instead of fancier hybrids. Common varieties may produce more nectar for the insects.
Limit your use of insecticides and herbicides, if you use them at all. Insecticides kill beneficial insects as well as those considered a nuisance. Herbicides are damaging to butterflies because they may eliminate sources of food for caterpillars and may poison them.
A particular pest species is often associated with a specific type of plant. By having a variety of plants, you reduce the potential for pest problems and therefore the need for chemical controls.
Several other elements can be added to enhance a butterfly garden. Place a few rocks in sunny areas to give the butterflies a good basking surface. Also provide wet sand or mud. This phenomenon, called puddling, provides minerals and other nutrients that the males “gift” to females during mating.
“Growing Green” is contributed by Lehigh County Extension Office Staff and Master Gardeners. Information: Lehigh County Extension Office, 610-391-9840; Northampton County Extension Office, 610-746-1970.