Butterfly Garden Design Guide

Topic Editor

Introduction



A butterfly garden is designed specifically to attract butterflies and their larva. Many people design for butterflies because they love to watch them in the summer. Watching them fly from flower to flower makes one feel amazed at the delicacy with which they fly so gracefully and, seemingly, without concern. Indeed, butterflies have been the subject of art, literature, and science for ages. They benefit gardens in tangible ways as well, as they are important pollinators. In this time when populations of beneficial insects are declining, designing a garden to attract pollinators is very important. Without pollinators, our apples, blueberries, and tomatoes would not produce fruit. In addition, designing a garden to attract butterflies will also attract other insects and birds to the area.

Butterflies are declining in urban and suburban areas. Urbanization has secluded the natural world into small segments that are far apart from each other. Native birds, mammals, and insects, including butterflies, have a hard time finding food and safe refuge. This is no small matter; loss of native insects leads to less food for native birds, all of which increases the competitive ability of invasive species. Biodiversity is essential to a healthy ecosystem, and creating a haven for butterflies supports diversity in an otherwise unwelcoming landscape. Homeowners can help bring populations of native species back into their area by providing food, shelter, and water for them. Planting a butterfly garden not only encourages butterflies, but also draws in beneficial insects that pollinate flowers, eat pest species, and feed local bird populations.

Butterflies are a specialized group of insects; together with the moths they make up the insect order Lepidoptera. This is the second largest order of insects (behind beetles), and moths make up about 95% of all lepidopterans. Creating gardens for butterflies also encourages moth populations, which are usually less showy and often fly at night, but are important for pollination and as food for birds and bats.

Moths and butterflies have distinct morphology, with two pairs of overlapping wings, often in colorful patterns, and a sucking mouth that curls up under its head when not feeding (called a proboscis). Lepidopterans undergo complete metamorphosis, which means they have four distinct life cycle stages: egg, larva (caterpillars), pupa (chrysalis), and adult. In order for a butterfly garden to be successful, it must address the needs of all four stages of a butterfly's life. (Photo: Western Tiger Swallowtail, Papilio rutulus.)

Site Needs


Sunny open areas
Butterflies need areas of low-lying groundcovers or lawn to rest in. Large flat surfaces, such as rocks or paving stones, should be included in these areas so butterflies can bask in the sun. Butterflies are cold-blooded, and therefore must warm up in the sun to get enough energy to take off. Mixing clover in with lawns is a great way to create this sunny open area. The clover serves as a nectar source for adult butterflies, and also encourages healthier lawns by fixing nitrogen in the soil.

Water and mud
Like all creatures, butterflies need water. Rather than just having open clear water, as in a birdbath or pond, consider a muddy or sandy area that remains moist. Butterflies can drink from between the particulates, and also obtain necessary minerals and salts suspended in the water. ou can create a sandpit by filling a small dish with sand and water and burying it in the ground. In addition, adding sand to the base of a birdbath works well. Even leaving areas of the garden that are already wet as open muddy spaces is a great benefit. Always be sure that there is a perch for butterflies, such as rocks or sticks emerging from the water, as they cannot land on water.

Shelter from wind
Butterflies are not quite as delicate as they appear, but they do require respite from wind and rain. Creating a buffer of taller shrubs or trees upwind from your butterfly garden will allow them to stay safe. These buffer plants can be native or non-native, evergreen or deciduous, but a mixture of these is best. Indeed, you can continue your butterfly garden into this refuge area by planting food and host plants for larva here.

Shelter at night and in the winter
Butterflies make it through the winter a variety of ways. Some, most notably the monarch butterfly, migrate south. Others hibernate, going dormant in any stage of their life-cycle, depending on species. Others die off completely, and repopulate the area from elsewhere in the spring. A successful butterfly garden addresses the needs of over-wintering butterflies. Mulch on the soil provides protection for pupae or larvae that drop to the soil for the winter; brush piles provide shelter, as do rocks and branches. Planting a variety of trees and shrubs creates shelter amidst their leaves and branches. The same things that give butterflies shelter in the winter will give them a place to rest at night, as well.

Food sources
A garden design must aim to feed both the larval and the adult stage of butterflies. Adults are primarily liquid feeders, and their main source of nourishment is nectar from flowers. They also feed on tree sap, decaying organic matter, and animal waste. In order to feed a variety of species for as many months as possible, plant flowers that bloom at different times of year and that have long blooming periods. In addition to nectar sources, it is often recommended you leave fallen fruit to rot on the ground to attract adults.

Larvae, on the other hand, usually feed on vegetation. Some are considered pests, such as tent caterpillars, cutworms, and the tobacco hornworm. Most lepidopteran larvae are not pests, however, and many will become adults that delight us. It is very important that in order to encourage butterfly populations, a garden must provide food plants for larvae. Damage to plants is usually minimal, and a diversity of plants will not only feed a variety of species, but will also hide minor leaf damage.

(One more note about food source plants for butterflies. A popular garden plant called butterfly bush (Buddljia davidii) is a Class B noxious weed in Washington and Oregon State. This shrub invades natural areas and displaces native species. In addition to being a harmful plant, the butterfly bush is only fed on by adult butterflies, and provides no food for larvae. See the Appendix for a list of plants that are better choices for a butterfly garden. Read Washington Noxious Weed Board's description of Buddleja)

In addition to providing all these things, a butterfly garden should be maintained without pesticides. This includes slug and snail bait, as they are harmful to insects. Pesticides create an environment that is inhospitable to wildlife and butterflies. Bacillus thuringiensis (Bt), a bacteria often used as an organic pesticide, cannot be used, as it targets lepidopteran species. Providing a variety of plants that attract beneficial insects as well as birds to the garden will keep most pest populations in check.

Plant Choices


Once the site is chosen for the butterfly garden (full sun, room for an open area as well as taller plants, moist well drained soils), the gardener can begin selecting plants for the garden. Some criteria to keep in mind while selecting plants are these:

  • Flowers with a strong fragrance attract more butterflies than unscented flowers. Scent and color advertise to insects that the flowers have nectar.
  • Groupings of similar flowers and colors in large patches will draw in butterflies, which are nearsighted, better than a mixture of colors.
  • Native plants are naturally suited to attract native butterflies.
  • Flowers in reds, yellows, whites, and mauves are more likely to attract butterflies than pastel colors.
  • Butterflies, like other insects, see ultraviolet light, and can therefore see color spectrums on the flowers that we cannot. Often flowers that provide nectar will have ultraviolet guides to pollinator species, such as lines pointing towards the center.
  • Composite flowers (like daisies or dandelions) are attractive to butterflies because they provide an easy perch to rest on while eating. Other plants that have clusters of flowers, such as honeysuckle or viburnum, also attract butterflies.
  • Gardens that have a variety of plants that bloom at different times of the year will attract the greatest variety of butterflies.
  • Some weeds, such as thistle, mustard family weeds, dandelion, and grasses, are marvelous host and food plants. If the garden space is large enough, you can provide an untended haven for weeds in a distant corner.
  • Avoid double hybrids of nectar plants. Often this genetic mutation eliminates the nectaries from the flower, or at a minimum makes it difficult for a sucking insect to locate them amidst the petals.
  • Growing some of the same species of flowers outside your designated butterfly garden will tie the butterfly garden to the rest of the space.

VISIT THE APPENDIX FOR A DETAILED PLANT LIST

Maintenance Tips


Maintenance of the butterfly garden should be more or less the same as with any flower garden. First, use as little pesticide as possible. Second, mulching the earth with coarse wood chip mulch will help build soil as well as provide shelter for butterfly pupa and other beneficial insects. It is recommended that you apply 2-3 inches of mulch to prevent weeds and maintain moisture in soil. Third, use caution when weeding and pruning to make sure you aren't removing butterfly eggs (which are often on undersides of leaves) or disturbing habitat. Consult with your local extension office to determine when eggs might be present. Fourth, watch for larvae in the garden. If there are plants you notice more larvae on, it may be a good idea to plant a few more of these around the garden. The same goes for adults. If you notice butterflies are particularly fond of a certain color or shape of flower, by all means change things around and add more plants.

References


Butterfly Gardening: Creating Summer Magic in Your Garden, by the Xerces Society in cooperation with the Smithsonian Institution. Vancouver, Canada: Whitecap Books, 1990.

Schenk, Marcus. Butterflies: How to Identify and Attract Them to Your Garden. Emmas, Pennsylvania: Rodale Press, 1990.

Grissell, Eric. Insects and Gardens. Portland, Oregon: Timber Press, 2001.

Haggard, Peter and Judy. Insects of the Pacific Northwest. Portland, Oregon: Timber Press, 2006.

"Butterfly Gardening." Washington State University King County Extension.
<http://king.wsu.edu/Gardening/documents/84ButterflyGardening>.

Lamb. S, Chambers, S., and Allen, N. "Create a Butterfly Garden." Jan. 2002. Oregon State University Extension Service <http://extension.oregonstate.edu/catalog/pdf/ec/ec1549.pdf>.

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