Butterfly gardening
Butterfly gardening is a way to create, improve, and maintain habitat for lepidopterans including butterflies, skippers, and moths. Butterflies have four distinct life stages—egg, larva, chrysalis, and adult. In order to support and sustain butterfly populations, an ideal butterfly garden contains habitat for each life stage.
Butterfly larvae, with some exceptions such as the carnivorous harvester, consume plant matter and can be generalists or specialists. While butterflies like the painted lady are known to consume over 200 plants as caterpillars, other species like the monarch, and the regal fritillary only consume plants in one genus, milkweed and violets, respectively.
As adults, butterflies feed mainly on nectar, but they have also evolved to consume rotting fruit, tree sap, and even carrion. Supporting nectarivorous adult butterflies involves planting nectar plants of different heights, color, and bloom times. Butterfly bait stations can easily be made to provide a food source for species that prefer fruit and sap. In addition to food sources, windbreaks in the form of trees and shrubs shelter butterflies and can provide larval food and overwintering grounds. "Puddling" is a behavior generally done by male butterflies in which they gather to drink nutrients and water and incorporating a puddling ground for butterflies will enhance a butterfly garden. While butterflies are not the only pollinators, creating butterfly habitat also creates habitat for bees, beetles, flies, and other pollinators.
Reasoning
Butterfly gardening provides a recreational activity to view butterflies interacting with the environment. Besides anthropocentric values of butterfly gardening, creating habitat reduces the impacts of habitat fragmentation and degradation. Habitat degradation is a multivariate issue; development, increased use of pesticides and herbicides, woody encroachment, and non-native plants are contributing factors to the decline in butterfly and pollinator habitat. Pollination is one ecological service butterflies provide; about 90% of flowering plants and 35% of crops rely on animal pollination. Butterfly gardens and monarch waystations, even in developed urban areas, provide habitat that increases the diversity of butterflies and other pollinators, including bees, flies, and beetles.Ground-truthing
Before buying plants and digging into the soil, "ground-truthing" is a necessary first step, Ground-truthing involves surveying a property in order to assess the current resources available. Some aspects to keep in mind are the following:- south-facing slopes
- natural wind breaks
- present plant species
- present butterfly species
Plants
The types of plants used in a butterfly garden will determine the species of butterflies that will visit the garden. Lepidoptera societies and the PLANTS database of the United States Department of Agriculture's Natural Resources Conservation Service provide state and county-level distribution maps of plants that are native to the United States. The Plants of the World Online database of the Royal Botanic Gardens, Kew, contains information on the taxonomy, identification, distribution, traits, threat status, and uses of plants worldwide, as well as many images of those plants. Published lists of host plants for butterflies and other pollinators can help select the plant species desired in the garden.While non-native plants can provide floral resources to a garden, they can also have an overall negative effect on butterflies and other pollinators. Therefore, it is often recommended to use native plants. It is also important to check invasive species lists to ensure that plants are not invasive in a given locality or region. The Invasive Plant Atlas of the United States and similar publications can help provide such information.
Depending on the hardiness zone, some butterfly-attracting plants include: buttonbush, blue mist shrub, purple coneflower, yellow coneflowers, marigolds, poppies, cosmos, mountain mints, sunflowers, salvias, some lilies, goldenrods, asters, Coreopsis, Mexican sunflower, daisies, joe pye weed, verbenas, lantanas, liatris, milkweed , zinnias, pentas, porterweeds, and others. A USDA conservation planting guide for Maryland recommends that, for optimum wildlife and pollinator habitat in mesic sites, a seed mix containing 30 seeds for each square foot of planting area should have 17.0% Asclepias syriaca by weight and 6.0% by seed. Another such USDA guide for Maryland states that for herbaceous plantings, non-competitive bunch grasses, little bluestem, purpletop ) may be included in a seed mix for native plants at a low rate — less than 25% of the mix based on pure live seed per square foot.
The eastern monarch migration largely depends upon only three milkweed species: Asclepias syriaca, Asclepias viridis, and Asclepias asperula. Butterfly gardens and monarch waystations in eastern and central North America should therefore feature one or more of those species, depending upon the areas in which the species are native.
Install flowering native trees and shrubs that also feed native butterfly caterpillars. For example, black cherry, a tree that is native to most of the eastern half of the United States, has white flowers that provide nectar to pollinators during the spring. P. serotina hosts the caterpillars of more than 450 species of butterflies and moths, including those of the eastern tiger swallowtail, red-spotted purple/white admiral, viceroy, and cherry gall azure butterflies and the cecropia, promethea silkmoth, polyphemus, small-eyed sphinx, wild cherry sphinx, banded tussock, spotted apatelodes, and band-edged prominent moths.
Sassafras, a tree that is native to the eastern half of the United States, has yellow, green, and brown flowers that provide nectar to pollinators during the spring. S. albidum hosts the caterpillars of 37 species of butterflies and moths, including the eastern tiger swallowtail, spicebush swallowtail, palamedes swallowtail and pale swallowtail butterflies and the cecropia, promethea silkmoth, polyphemus, imperial, and io moths.
Spicebush, a shrub that is native to the eastern half of the United States, has white, yellow, and green flowers that also provide nectar to pollinators during the spring. L. benzoin hosts the caterpillars of the spicebush swallowtail and eastern tiger swallowtail butterflies and the promethea silkmoth.
Avoid cultivars of plants unless they are more resistant to diseases than their native parents or that investigations have proven to be more beneficial to pollinators than their parents. Many cultivars are sterile and produce no nectar or pollen. As a result, their flowers do not benefit butterflies and other pollinators. Some have "double flowers". Their reproductive parts have been converted into extra petals and therefore do not produce floral rewards for pollinators. Some cultivars have reduced nutritional benefits, and have not been studied enough to identify those that may be harming pollinators.
Cultivars with features that significantly affect flower structure and/or color are those that are likely to alter their appeal to pollinators. Those selected for foliage color may be toxic to insects. Studies have shown that altering leaf color, and the chemical changes that this implies, reduces a plant's ability to serve as a resource for herbivorous insects.
Buddleja davidii, which is often called "butterfly-bush", attracts many butterflies. Although it originated in China, it is presently planted in many parts of the world in which it is non-native. In such settings, the plant feeds many native butterflies and other adult pollinators, but not many of their larvae. As B. davidii is invasive in some areas, plantings of the species are controversial. To prevent seeding and to promote further flowering, its blossoms need to be removed as soon as they are spent.
A number of Buddleja cultivars have become available that have a variety of sizes and blossom colors. University studies have suggested that nectaring butterflies have greater preferences for some of these than for others, with Lo & Behold 'Blue Chip' and 'Pink Delight' heading a list of eleven.
Some Buddleja cultivars are either sterile or produce less than 2% viable seed. The state of Oregon, which designates B. davidii as a "noxious weed" and initially prohibited entry, transport, purchase, sale or propagation of all of its varieties, amended its quarantine in 2009 to permit those cultivars when approved or when proven to be interspecific hybrids. Monarch Watch recommends planting only male-sterile "Flutterby" cultivars.
It is important to avoid purchasing plants and seeds treated with insecticides such as neonicotinoids. Although not yet conclusive, there is increasing evidence that neonicotinoids can have negative effects on pollinating insects, including butterflies.