By Whitney Cranshaw, Colorado State University Cooperative Extension Entomologist
Have you ever been tempted to purchase a collection of ceramic butterflies -- you know, those beautiful creatures displayed in gift stores in glass and brass cases?
Instead of purchasing the replica, you can observe the real thing in a natural setting. With a little planning, you can create a garden that will attract and keep butterflies.
The Front Range of Colorado attracts about 450 butterfly species, among the greatest diversities found anywhere in the world.
To entice the butterflies, you must provide for the insects' basic needs, both in the adult and caterpillar stages.
Swallowtail "caterpiller" on fennel
Shelter and food are the two most important considerations. To provide shelter, choose a garden site with some protection from Colorado's strong winds. Buildings or existing landscaping usually are sufficient; In their absence, a hedge or windbreak may provide the protection butterflies need.
The most obvious feature of a butterfly garden are nectar-bearing flowering plants that provide food for most adult butterflies. Not all plants are good nectar sources. Among the best plants are asters, bee balm (Monarda), butterfly bush (Buddleia davidi), butterfly plant (Asclepias tuberosa), bush cinquefolia (Potentilla fruticosa), cosmos (Cosmos ssp.), Gaillardia, lilac (Syringa vulgaris), marigolds, rabbitbrush (Chrysothamnus nauseosus), sunflower (Helianthus), sweet pea, thistles, verbena and zinnia.
Some butterflies, however, are not nectar feeders, particularly many early-season species. The Nymphalidae, which include attractive butterflies such as Weidemeyers Admiral, Mourning Cloak and Hackberry butterflies, feed on sap flows, rotting fruit and even animal dung. Periodically placing cut fruit around the garden or providing fruit-bearing trees may attract these species. The ooze from a tree wound also might attract some butterflies.
Males of some species often collect in damp areas. The reason for these `mud puddle clubs' is unclear, although it's possible that dissolved minerals in the water provide useful nutrients. By providing a moist spot in the garden, you might be able to retain these types of butterflies.
To design a butterfly garden, plant desired plants in masses, rather than scattered areas. Try to provide a sequence of desirable flowers and plants throughout the growing season. Although some butterflies may be present summer through fall, butterfly visits typically peak during mid-to-late summer. It's particularly important to provide nectar and other adult food sources at this time.
Don't forget food plants used by the caterpillar stage of butterflies. Female butterflies seek out specific types of plants for egg laying; the presence of these plants can encourage establishment of a native butterfly population. The caterpillar stages often are unusual in form or color and can be interesting to observe.
PLANTS USED BY THE CATERPILLAR STAGE OF SOME COLORADO BUTTERFLIES
To encourage this butterfly establish these plants:
Now for the bad news. Some conflicts can arise in butterfly gardening. Caterpillars can eat some plant leaves, although seldom does nibbling occurs at harmful levels. One exception is the European cabbage butterfly, the common cabbage worm of home gardens. These fellows can, all too often, spoil a head of cabbage or broccoli and may need to be controlled on these plants.
A few others may become pests. The strikingly colored caterpillar of the black swallowtail butterfly, the parsleyworm, is well known to gardeners who plant parsley, fennel or dill. The caterpillar of the variegated fritillary may reside in the pansy patch and chew a few leaves. But, in larger plantings, designed for ornamental purposes, the feeding by these insects is rarely noticeable.
Most insecticide use is incompatible with a butterfly garden. Caterpillars are highly susceptible to most chemicals, as well as Bacillus thuringiensis. Fungicides, selective miticides and insecticidal soaps generally, however, are compatible with butterfly gardens. To encourage butterflies, you'll need to make a conscious decision not to treat with insecticides, a decision made easier by using plants with fewer pest problems.
Your butterfly garden may have a `wild' look. Some of the most effective plants for attracting butterflies do not have a compact growth habit and some of the plants are even considered weeds in other settings. Careful landscape design can minimize this problem.
Photographs courtesy of Judy Sedbrook.
© CSU/Denver County Extension Master Gardener 2010
888 E. Iliff Avenue, Denver, CO 80210
Date last revised: 01/05/2010