Butterfly Gardening: The Basics

Monarch Butterfly (Danaus plexippus) nectaring on Butterfly Milkweed (Asclepias tuberosa)

Butterflies, Moths, and Plants

As mentioned last month, plant choices in a garden drive food choices for wildlife: nearly everyone knows that Monarch butterflies require Milkweed plants for their caterpillars, but this is only the tip of the proverbial iceberg in terms of plant/insect relationships!! Many species of butterflies and moths do not have the host plants one would expect: for example, Luna Moth (Actias luna) caterpillars feed on birch (Betula sp.) trees and Sweet Gum (Liquidambar styraciflua) along with some other species of tree, and the adults don't eat at all. So how do you tempt some of the flashier butterflies and moths to your garden? There are a few basic things any gardener can do to attract these gorgeous winged visitors.

Research Your Area!

One of the most crucial steps a gardener can take for attracting butterflies is to look up what butterflies are native to your area, the host plants needed for their caterpillars, and the host plants they nectar on. This might seem like a lot of work, but a quick google search of "butterfly host plants (your state name here)" usually makes for a very effective strategy, because you don't have to put this information together from scratch.

Red-Spotted Purple (Limenitis arthemis) "puddling," a behavior that seems to be a way for butterflies to collect nutrients

Butterfly conservation and education groups have often already put together charts of butterflies you are likely to see in your garden, and the host plants they (and their caterpillars) require. For example, this is a list of butterflies and their host plants in New Jersey, and this is an article (including a very similar list) on butterfly gardening in Pennsylvania. It must be said, however, that not all lists are created quite equal: the New Jersey list was put out by the Native Plant Society of New Jersey, so it is sensitive to the impact of invasive species on the landscape. The Penn State extension article on the butterflies of Pennsylvania has a lot of good information, but falls down on the invasive plant front, which leads us to our next point.

Female Tiger Swallowtail (Papilio glaucus) nectaring on Wild Bergamot (Monarda fistulosa)

Regarding Butterfly Bushes and Cultivars

As tempting as it seems, and as popular as this plant is, Butterfly Bush (Buddleja or Buddleia, especially Buddleia davidii, also known as summer lilac) is an invasive species. That means that it is a non-native plant that spreads into the surrounding area and harms the environment by aggressively taking the place of native plants. According to Invasive.org, which keeps a curated list with information of invasive species in the United States, "Buddleja... readily invades disturbed sites and riparian areas. Although butterflies will use this plant as a nectar source their larvae cannot survive on it. By replacing native larval food source plants butterflybush can have a negative impact on wildlife." However well-intended a Butterfly Bush may be, these plants will invade the landscape, given the opportunity, replacing plants on which butterfly species can reproduce. It is not unheard-of for some butterflies to lay eggs on Butterfly Bushes in a case of mistaken identity, but as the larvae cannot survive there, the caterpillars will die and the butterfly population will suffer as a result. Planting a flowering shrub in your garden where butterflies may shelter during harsh weather is a good idea, but planting a Buddleja is not. In the same vein, avoid cultivars when you can! Cultivars are usually selected for their appearance; when the plant is changed, the value of the plant for butterflies may also be changed. For example "double" flowers sacrifice their reproductive parts in order to produce more petals... which means no pollen, no pollination, and no nectar for the butterflies (and no seed production for birds)! Butterflies and native plants evolved side-by-side, so butterflies are best able to use straight species of native plants in your garden.

So if I Plant Native Plants... Who can I Expect to See?

In an established butterfly garden, you could simply put out colorful sponges soaked in sugar water to attract butterflies, but without nearby host plants for the caterpillars, some species will just never show. One of the visitors you may see in your garden this summer is a butterfly that looks a lot like a Monarch... but isn't! Viceroy butterflies mimic Monarchs to discourage predators:while Monarchs are brightly-colored to warn birds that they taste bad (which is what happens when you're raised on a plant even the deer won't eat), Viceroys are brightly-colored simply to try to convince birds they're Monarchs. In reality, Viceroy caterpillars eat Willows, Poplars, and Cottonwoods rather than Milkweeds. The adults, however, prefer to nectar on composite flowers such as Asters, Goldenrods, and Joe-Pye Weed.

Viceroy Butterfly (Limenitis archippus) waiting patiently (or perhaps not) for this Goldenrod (Solidago sp.) to flower!

Tiger Swallowtails, flashy yellow or blue and black butterflies whose caterpillars feed on Black Cherry Trees (Prunus serotina), are also commonly found in the midsummer. These interesting butterflies are sexually dimorphic, meaning that the females of the species often look quite different from the males! While the males are bold shades of yellow, blue, and black, the females have two different color morphs. Some may have the same coloring as the males, but many are blue, black, and red, and look more like Red Spotted Purple butterflies (whose young also feed on cherry trees), or other species of swallowtail such as the Spicebush Swallowtail, (which feeds on Sassafras and Spicebush). Although several species of Swallowtail butterfly are native to the northeast, female Tiger Swallowtail butterflies are easily distinguished from Red-Spotted Purples due to the fact that Swallowtail butterflies have tails on their wings!

Male Tiger Swallowtail (Papilio glaucus) nectaring on Yarrow (Achillea millefolium)

Many species of Fritillaries may also be frequent visitors to your garden, if Fritillary host plants are present: most fritillary caterpillars feed on violets, and male adults patrol areas they have staked out to look for females. Most summers, the Toadshade meadow is aflutter with Fritillary species, who seem to have a particular fondness for nectaring on Milkweed flowers!

Pearl Crescent Butterfly (Phyciodes tharos)

Is it worth it?

One of the most exciting things about a butterfly garden is the variety. There are so many species of butterflies and moths in North America, and each one has something different to offer! From the Buckeyes (Junonia coenia), with their gorgeous and distinctive spotted pattern, to the Hackberry Emperors (Asterocampa celtis), who use American Hackberries (Celtis occidentalis) as a host plant and are curious enough to ride around on your hand or head, Hummingbird Clearwing Moths (Hemaris thysbe), who can easily be mistaken for hummingbirds, or Mourning Cloaks (Nymphalis antiopa), who overwinter as adults and begin flying earliest in the Spring, butterflies and moths offer endless variation and interest. Without a selection of host plants, the species of butterflies and moths visiting your gardens will be significantly more limited. In an area with a variety of host plants, however, a diverse range of colorful visitors often adorn the flowers of a garden and bring it alive!!

Great Spangled Fritillary (Speyeria cybele) nectaring on Butterfly Milkweed (Asclepias tuberosa)