Building a Butterfly Garden

— Written By and last updated by Kate Holt

black swallowtail butterflyBlack swallowtail butterfly feeds on a zinnia blossom. John Reintjes, Master Gardener Volunteer

Butterfly watching has gained a lot of interest in recent years. Butterflies are colorful and interesting, adding an element of moving beauty to the garden. North Carolina is home to more than 175 species of butterflies, making our state an ideal area for butterfly watching. With a little bit of planning you can develop a garden that will attract a diverse population of butterflies.

Butterflies have a distinct life cycle. A butterfly’s life begins as an egg, which is generally laid on the leaf of a specific host plant. A host plant is a plant that caterpillars like to eat. Caterpillars are voracious, although picky eaters. Caterpillars chew and eat leaves. When small, caterpillar feeding may not be obvious, but as the caterpillars (and their appetites) mature, they consume large quantities of leaves over a relatively short period of time. After a few weeks of feeding, the caterpillar molts into a mummy-like stage with a hard protective casing called a pupa or chrysalis. While in the chrysalis, the caterpillar transforms into an adult. At the end of about two weeks, the adult emerges from the chrysalis, spreads and dries its wings and begins searching for food and a mate. After successful mating, the female begins her search for a host plant on which to deposit her eggs. As an adult, butterflies actually feed entirely different than caterpillars. Adult butterflies may not feed, or they will use a long proboscis (straw-like mouthpart) to sip nectar from flowers. In the process, they serve as pollinators – moving pollen from one plant to the next. In some cases, adult butterflies feed on rotten fruit or tree sap.

This elaborate life cycle dictates that a successful butterfly garden will need to provide host plants for the larvae as well as nectar plants or other appropriate food sources for the adults. Native plants (plants that are indigenous to our area) are preferred for butterfly gardens. Native plants are the plants that regional butterflies have adapted to and evolved with. Most ornamental plants are bred for color and bloom size, rather than nectar production so while these “improved cultivars” may be attractive to us, they may provide little benefit to wildlife.

You will want to choose a variety of nectar plants that will provide food throughout the growing season since different species of butterflies are active throughout the year. Choose flowers with blooms of different sizes and depths – smaller butterflies have shorter mouthparts and are unable to reach the nectar in larger blooms while larger butterflies favor larger flowers. Make sure that you consider the moisture and light requirements of plants before placing them in your butterfly garden – choose plants that are suited to your particular location. Most butterflies are active only in the sun so many butterfly friendly plants are also suited to sunny locations. Take this into consideration when selecting the location for your butterfly garden.

Besides plants, there are other important considerations. Butterflies need shelter and overwintering areas. Most species survive the winter by hibernating as caterpillars, pupae or adults. When possible, leave snags (standing dead trees) or brush piles in the landscape for overwintering. Throughout the growing season and fall, leave dead flower heads and dead foliage on the plants or you may accidentally remove eggs or pupating butterflies.

Provide a mud puddle or damp sandy area for male butterflies to congregate around as well as a few large flat rocks or a small area of dark pebbles for butterflies to perch on while basking in the sun. Fruit peels, cores and rotten fruit can be placed in a discrete location in the garden where they will attract butterflies that eat rotting fruit.

Another important consideration is to minimize the use of pesticides. Insecticides, which are chemicals designed to kill insects, also kill butterflies and other beneficial insects. If caterpillars are eating your favorite plants (for instance when black swallowtail butterflies feed on parsley or fennel), choose a few plants to serve as host plants and relocate caterpillars from other plants to your dedicated host.

Finally, do not release purchased butterflies. Whether as part of a celebratory event like a wedding or to stock your garden, releasing purchased butterflies is not a good idea. Released butterflies can spread disease to the native butterfly population or cause other problems.

To learn more about developing a butterfly garden, see NC State Extension’s Butterflies in Your Back Yard.  This publication includes everything you need to get started, including a list of common butterflies in NC as well as detailed lists of larval host and adult nectar plants and butterfly garden design ideas.