Plant a Butterfly Garden

By William Young

For less effort than you might think, you can create a butterfly garden in your yard. In addition to creating habitat for our colorful winged friends, you will be doing the earth a favor by using less fossil fuels, water, and herbicides. Even those in urban areas will be amazed at the butterflies that find their way to your yard. So, what are you waiting for? Basically you are making a prairie.

Pick a sunny portion of your yard with good air circulation. The site should be protected from strong winds. The hotter and drier the site, the better, so start with south and east-facing slopes or faces. The cool, north facing slopes are good for ferns and woodland wildflowers. The easiest way to prepare an existing lawn is to rent a sod cutter and use it to remove the top three inches of sod. Then prepare and plant (or seed) the area immediately. Do not turn the soil over, as this will introduce more weeds than leaving the soil untilled. Plant nursery plants for sites under 1,000 square feet or so, and seed areas larger than that. Spring is best for planting and late spring is best for seeding. Transplants can also be planted in early fall. Use three to four inches of clean straw as a mulch to keep weeds down. Planting plugs is better than seeding in that you can label the transplants as you put them in the ground to later distinguish them from the weeds.

A second way to convert lawn to prairie is to mow down to the stubble, then spray Roundup. For your information, the active ingredient in Roundup is glyphosphate, which acts to interrupt the process of photosynthesis. It is harmless to the rest of the ecosystem. We have fact sheets on this available at your request. Wait a week or two after spraying before setting out your new transplants.

Plant plugs (1/2 grasses and 1/2 wildflowers or 1/3 grasses to 2/3 wildflowers) right through the turf. Here at Dawson we have a specialty seeder that "drills" the seed right through the sod. The less soil you expose to daylight the better. The prairie wildflowers and companion grasses grow deep roots that eventually out compete the weeds, especially the short-lived annuals. Have patience; it may take a year or two for the natives to knit together. Initially, you can spot-spray for weeds or do some hand pulling. Pay more attention to perennial, persistent weeds than annuals. Early intervention pays off with weed control.

Plant the shorter bunchgrasses to best show off the flowers. Little bluestem, Prairie dropseed, and sideoats grama are native grasses that best show off the perennial flowering plants provide fall interest and help the wildflowers to squeeze out the weeds. You may be tempted to leave out the grasses in favor of the more showy wildflowers. I urge you not to do that for two reasons. One, the grasses have shorter, more compact root systems that combine with the deeper-rooted perennials to squeeze out the weeds, and two, the grasses are more persistent late in the season and provide nice fall colors. Also, the grasses provide some of the larval food for the caterpillars.

If you elect to seed rather than plant plugs, you can use a regular mowing regimen to reduce weeds in favor of the long-lived native flowers and grasses. Mow regularly at a 4 to 6 inch height until the planted seeds grow beyond that height (they will put down roots first). Once they become established, the natives will squeeze out the weeds by virtue of their superior root systems and drought tolerance.

For plantings, mow once a year in late fall (after the seed heads have dropped) or mow very early in spring, before the nesting season. Consider a controlled burn program, but do not try to implement a prescribed fire program without sufficient knowledge of how to do it. Call the Native Plant Society and we will recommend someone to help you. One annual burn or one or two annual mowings is the recommended maintenance for your prairie. Watering your prairie will just encourage weeds.

Now that you have the basic prairie in place…

If you want to have butterflies (and birds) around your wildlife garden, be sure to plant native grasses and wildflowers in as many places as possible. That means not only in the garden itself but scattered all around the yard. The smaller milkweeds like butterfly weed (Asclepias tuberosa) are attractive selections for more civilized parts of the yard. In the wilder areas, you can grow common milkweed (A. syriaca) to provide food for monarch caterpillars and well as the caterpillars of swallowtails, cabbage whites, common sulfurs, many hairstreaks, question marks, common blues, great spangled fritillaries, red admirals, and dozens of species of the skippers. Goldenrods and asters are used by many species of butterflies.

The flower preferred by the butterfly is not necessarily the food of choice for the caterpillar. The leaves of most woodland grasses (purple-top, Tridens flavens) are favorites of the caterpillars of the large wood nymph and the tawny-edged skipper, but are overlooked by butterflies because they offer no nectar. Monarch butterflies are drawn to members of the composite (daisy) family, as well as butterfly weed and other milkweeds.

Larval foods include the Hawthorns (Crataegus spp.), Spicebush (Lindera benzoin), Elm, Wild cherries and plums (Prunus spp.), Oaks (Quercus), hackberries (Celtis), Clethra, Viburnum, Willows (Salix), sumacs (Rhus), dogwoods (Cornus), and walnuts (Juglans).

Adult food (flowers) include the milkweeds, asters, thistle, Sunflowers, Lilac, Phlox, Eupatorims, yarrows, goldenrods, dotted mint, white turtlehead, Buttonbush, Lupines, Ironweed, Blazingstars, Black-eyed Susan, Lobelia, Monarda, Coneflowers, and, of course, New Jersey tea (Ceanothus).

If you build it, they will come…

Nearly overnight, you will be visited by birds, insects and other wildlife. If you include a water source, that is even better. Once the wildlife comes, a "hands-off" approach is better- refrain from chemicals or fungicides in and around your prairie garden. Once established, your butterfly garden will bring years of enjoyment with minimum maintenance. Look for Richie Brown's column for other ideas on how to naturalize your garden and foster wildlife habitat. Not only are you setting a good example, your yard will come alive with new life. Drop us a line and tell us how you are doing, and maybe we will feature your new prairie garden in an upcoming newsletter. The butterflies and the birds will thank you!

References

Diboll, N. and Van Abel, B. 1995. Prairie Nursery Catalog. (For a catalog 1-800-476-9453)

Marinelli, J., editor. 1999. Easy Lawns Low Maintenance Native Grasses for Gardeners Everywhere. Brooklyn Botanic Garden.

Turfts, C. and Loewer, P. Gardening for Wildlife. 1995. Rodale Press, Emmaus, Pennsylvania.

Swain, Robert L. Personal communication.