Fall Butterfly Season Back »

A monarch butterfly on an aster flower.


It’s almost fall and there are probably still lots of flowers in bloom in people’s gardens at this time of year, which is good news for butterflies that need those flowers as a source of food. Flowers provide nectar which is food for newly emerged adult butterflies. Butterflies need energy to sustain themselves and in the case of the monarch, to help them survive their migration south.

South Dakota is home to 172 species of butterflies, according to Gary Marrone, author of the Field Guide to Butterflies of South Dakota (2002), who has been collected butterflies for more than 30 years. While some of these will appear in gardens earlier in the summer, many of the common species are prevalent in late summer. The most well-known butterfly, the monarch (Danaus plexippus) is usually pretty rare until mid-summer. The offspring of the adult monarchs that migrated to Mexico last year need to make their way back north before we will see them out in our South Dakota gardens in July. I am happy to report that the number of monarch butterflies in McCrory Gardens is much higher this year than what we saw over the last two years. It will be interesting to see how many of them mass up when it is time for them to begin their arduous journey all the way to Mexico in a few weeks. There were still larvae and pupae visible on milkweeds and adjacent plants that had yet to emerge as adults in early September and join the others that were actively feeding at McCrory Gardens over the last few weeks.

Monarchs

Monarch caterpillar feeding on butterfly weed. Monarchs on Liatris.
 

Monarch larvae (caterpillars) depend on milkweed (Asclepias) as their primary source of food. Female monarchs lay their eggs exclusively on milkweed. Once the eggs hatch, the larvae use their chewing mouthparts to eat milkweed leaves for several weeks, molting every week or so until they wander off to form a chrysalis. They emerge from the chrysalis as the familiar orange and black butterflies that so many of us enjoy seeing in our gardens. Adult monarchs have mouthparts that resemble a drinking straw that they uncoil to insert into flowers to sip nectar. They still like to feed on milkweed flowers, but they also visit a wide variety of plants.

The number of wild milkweeds has been declining in recent years due to drought, and diminishing habitat. As fence rows are removed from agricultural lands, highway right-of-ways are mowed for hay, and CRP lands are put back into row-crop production, there are fewer places for milkweed to thrive.

It takes multiple generations of adults to continue the reverse migration back to the northern part of the United States. If there are fewer food plants along the way, fewer monarchs are able to produce offspring to make that trek. Thankfully that message has been received and many home gardeners are planting Asclepias species or allowing the wild species, like common milkweed (Asclepias syriaca) to grow in their gardens and other areas of their land to provide a place for the monarchs to feed and lay eggs.

Other Common Butterflies


Painted lady butterfly on aster.

Other common butterfly species found in South Dakota include the Painted Lady (Vanessa cardui), Eastern Tiger Swallowtail (Papilio glaucus), Eastern Black Swallowtail (P. polyxenes), Clouded Sulphur (Colias philodice), Red Admiral (Vanessa atalanta rubria), Regal Fritillary (Speyeria idalia), Eastern Comma (Polygonia comma), Question Mark (Polygonia interrogationis), Melissa Blue (Lycaeides melissa), Mourning Cloak (Nymphalis antiopa), and the Common Wood-nymph (Cercyonis pegala nephele). Each of these butterflies has their preferred plants for caterpillars and adults. Some butterflies will also feed on tree sap, and decaying fruit. Some butterflies, especially those that are long-lived, will land on animal droppings urine, mud puddles and even carrion to obtain minerals and nutrients not found in flower nectar.

Eastern Tiger Swallowtail – Papilio glaucus. Eastern black swallowtail on salvia.
 

Butterfly-Friendly Plants: Aster (Asteraceae)

Butterflies mostly feed on flowers, using their tube-like proboscis, to sip nectar. In general, their favorite flowers are those from the Aster (Asteraceae) family. There are many examples of native plants that belong to this family as well as dozens of other species of non-native plants that are commonly grown in our gardens. Butterflies seem to like these flowers for a few reasons. First of all the flowers are of a special type known as composites, meaning that each main flower is actually made up of dozens or even hundreds of individual florets, each one potentially being a source of nectar. Often times there might be a dozen florets in bloom at one time so a butterfly can spend a fairly long time feeding at one flower, sticking its proboscis into each individual floret. Aster flowers are also quite accommodating in that they are usually fairly large, flat and offer the butterflies plenty of room to rest on the flower while they are feeding. Some of the butterfly favorites in the Aster family include Purple Cone Flower (Echinacea), Zinnia, Iron Weed (Vernonia), Joe Pye Weed (Eupatorium), Blazing Star (Liatris), and of course Aster. They will also actively feed on some plants that we ordinarily think of weeds like Dandelion (Taraxacum) and most of the thistles (Cirsium and others).

Eupatorium in flower with monarchs. Painted lady butterfly feeding on aster.
 

Mint Family (Lamiaceae)

The Mint family (Lamiaceae) is another family of plants that are very attractive to butterflies. Plants in this family have a spike type flower that again provides multiple florets for the butterflies to feed on. However, unlike the Aster family, the flower spikes of the mints are generally elongated and upright. But they still provide plenty of leg room and places for the butterflies to hang on while feeding. They seem to be particularly fond of Anise Hyssop (Agastache), Bee Balm (Monarda), and the various species of Salvia.

Monarch on Agastache. Eastern Tiger Swallowtail Papilio glaucus feeding on Dianthus.
 

Milkweeds

Milkweeds, besides being essential for monarchs, are also visited by other butterflies. Common milkweed (Asclepias syriaca) does have somewhat attractive flowers but its penchant to spread rapidly by both seed and underground stems (rhizomes) combined with its rather coarse texture do not make it a favorite of gardeners. The most commonly grown milkweed, Butterfly Weed (A. tuberosa) is an attractive and long-lived, native perennial. It has stunning orange flowers and grows into a medium sized perennial plant (2-3 ft tall and wide). While it can spread by seed, it is normally not aggressive. Another, fairly popular milkweed is the Swamp Milkweed (A. incarnata). This is a taller plant with more slender leaves than common milkweed. It is native to wetter areas of the prairie but will also grow quite well under most garden situations. It may occasionally be short lived but is likely to pop up in another location in the garden if it is allowed to go to seed. All of the milkweeds develop a pod that is filled with seeds, each attached to its own little fluff of silky white hairs that allow it to be carried for some distance before settling to the ground to potentially starting a new plant.

Asclepias tuberosa in bloom. Asclepias incarnate and sphinx moth.
 

Butterfly Bush (Buddleia)

Butterfly Bush (Buddleia) is another plant that you might consider adding to your garden if you wish to attract butterflies. As the name suggests it is famous for its attraction to butterflies. Its flowers come in a wide array of colors, ranging from white to lavender, purple, burgundy, pink and red. Like some of the other favorites of butterflies, the flowers are borne in clusters with multiple flowers open at one time so there is plenty of food available to a butterfly that happens to find a plant in bloom. The flowers are sweetly scented and make good cut flowers for gardeners to enjoy too. One problem with Buddleia is that the plants are not completely hardy in our climate. It is actually a woody shrub in warmer climates but for us in South Dakota and other northerly areas, it acts more like a herbaceous plant, mostly dying to the ground each winter then hopefully growing back again from surviving buds, closest to the ground. But, even if your plant does die to the ground during its first winter, I think they are worth it.

Other Butterfly-Friendly Garden Features

Flowers are just one part of a butterfly-friendly garden. In addition to nectar, butterflies need water besides what they get while sipping nectar. Often a bird bath will do but they prefer a very shallow pool from which to sip. Standing water in the depressions in a rock or paver pathway works great. Whatever water source you choose, make sure to change it regularly to avoid creating mosquito habitat. Another thing to consider is our nearly constant wind. Butterflies are often pretty strong fliers but if you can provide some protection from the wind with taller vegetation or an actual windbreak that will enable them to feed much more easily on windy days. Butterflies also need places to sun themselves. They need to be able to warm their bodies to at least 86° F before they will become active. So providing places for them to “hang out” and warm up will be appreciated.

Additional Resources

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