In a recent conversation a man mentioned how caterpillars were devastating his trees. He had no idea what they were but just knew that no good could come of the chewed leaves and other evidence of life he was finding in his trees. Now it is true that there are some truly destructive caterpillars and caterpillar-like larvae that will do a number on trees, shrubs and perennials. (Anyone else remember running around in the backyard as the chemical-dropping planes worked to control the gyspy moths on oaks in South Jersey after years of defoliation?)
In the same conversation, the gentleman discussed Monarchs and his want to protect butterflies and plant milkweed to help these familiar orange and black winged wildlife. When it was suggested that monarch caterpillars eat leaves of plants, that was just fine with him.
Curious – unknown caterpillar = bad, milkweed caterpillar = good. Though his concern for the plight of the Monarch is noble, perhaps a broader view of the benefits of embracing the caterpillars in the garden would benefit butterflies and pollinators of all sorts.
When planting the oft sought after “Butterfly Garden” or “Pollinator Garden” many folks forget about the creepy crawly stage of the insects they are trying to attract and support. The gardener’s eyes are filled with visions of jewel-toned butterflies hovering in the garden sipping nectar from equally stunning floral displays. The wonderful thing is that when we welcome caterpillars into the garden we also put out the welcome mat for a great diversity of birds and other wildlife. In a recent article about gardening for wildlife, Douglas Tallamy explains 6,000 – 9,000 caterpillars are required raise a clutch of chickadees. While monarch caterpillars are known to be toxic to birds because they solely ingest the toxic sap of milkweed ( like that in the 5 types we have) and therefore not necessarily a food source for birds, many other caterpillars are less picky and more tasty.
While we carry a tremendous variety of nectar plants suitable for any ‘butterfly’ or ‘pollinator’ garden, we have a terrific number of plants just right for caterpillars, known as larval host plants. And we know you may not want to plant these simply to create a buffet for the local songbird population but, don’t worry, these plants will ensure the garden will have a diversity of plant species, colorful blooms, insects and birds.
Some plants are equally good larval hosts and nectar plants. Others, like many grasses and sedges, are perfect larval host plants, supporting the caterpillars until they are ready to transform into their flying selves and float off to the more colorful nectar plants.
- Asters – whether you are ‘old school’ and still call them Asters or have accepted the new-fangled Eurybia (like the White Wood Aster), Doellingerias (Like the Flat-topped White Aster) or Symphiotrichums (like the Frost Aster) – all make good nectar AND larval plants. Plant these and attract the Pearl Crescent, Harris Checkerspot and Silvery Checkerspots.
- Milkweeds – it is unfortunate that the word ‘weed’ is in the name of this plant because some people treat it as one. Some species of this native perennial can be aggressive and Common Milkweed has been known to colonize an area where it is happy, but there are many other types of milkweed. In fact, there is a milkweed for any garden. The leaves are enjoyed by Monarch Caterpillars but the flowers are visited by many butterflies, bees, beneficial wasps, flies and beetles. Try Asclepias incarnata in your Wet Meadow. For drier sites and nutrient poor soils try the bright orange Asclepias tuberosa. For a drier meadow try Asclepias vericillata.
- False Indigos – Attract caterpillars of Frosted Elfin, Wild Indigo Duskywing and Orange Sulphur Butterflies as well as the caterpillars of Io moths and skippers to the bright yellow blooms of Baptisia tinctoria and the purple spring blooms of Baptisia australis, B. alba var. alba, and Baptisia minor.
- White Turtlehead – Baltimore Checkerspot caterpillars find the leaves of Chelone glabra irresistible.
- Hibiscus – It is no surprise this perennial with large tropical-looking flowers attracts a variety of visitors. The Gray Hairstreak finds the developing seeds of Swamp Mallow as equally irresistible as the flower, while Painted Ladies and Common Checkered Skippers eat the foliage. Moths, equally as beautiful as butterflies and equally as valuable as pollinators and food sources for other wildlife, also start out as caterpillars. The hibiscus also hosts the intriguingly named Delightful Bird Dropping Moth as well as the Io Moth, Pearly Wood Nymph, and Yellow Scallop Moth caterpillars.
- Goldenrods – often maligned as the summer blooming plant that causes allergies (they’re not…read more here) these native perennials are caterpillar magnets! Great late pollen and nectar source for many types of insects, earlier in the year you will find Baltimore Checkerspot Caterpillars on Blue-Stem Goldenrod and Wrinkle-leaf Goldenrod.
- Ironweeds – Ladies love a Vernonia – Painted Ladies, that is. Both the American Painted Lady and the Painted Lady will use the rough, dark green leaves of Ironweeds.
- Violets – A list of butterfly larval host plants wouldn’t be complete without mention of the violet. The amethyst spring flowers are surrounded by heart-shaped leaves favored by Frittilaries.
- Golden Alexanders – Like other members of the Apiaceae family, Giant green Black Swallowtail caterpillars can be found feasting on the leaves of both Heartleaf Alexander (Zizia aptera) and Golden Alexander (Z. aureus)
- Given the understated flowers on Carex species, one wouldn’t expect them to be on a list of butterfly plants. The graceful Palm Sedge is known to support the larval stages of skippers. Look for caterpillars of Appalachian Brown and Eyed Brown Butterflies on the leaves of Tussock Sedge, Grays Sedge, and Plantain Leaved Sedge. In addition to the Appalachian and Eyed Brown Butterflies, Awl-fruited Sedge also supports the larva of Black and Long Dash Butterflies, Duke, Dion and Broadwing Skippers and the Mulberry Wing.
- Just like sedges, the flowers aren’t the show for butterflies on our native grasses. It is the foliage and sometimes the seeds the caterpillars are after. The Zabulon Skipper loves Purple Love Grass. Switch Grass appeals a variety of skippers, and the Northern Broken Dash butterfly. A garden with Little Bluestem will also soon find skippers aloft. And if you are looking to add the Common Roadside Skipper or the Northern Pearly Eye to your Butterfly life list be sure to plant some Northern Sea Oats.
- The exotic purple flowers of the native Passion Flower will probably attract perfect strangers to your yard. In addition, look for the larva of Gulf Fritillary and Red-banded hairstreak butterflies.
- Hummingbirds flock to the coral tubular flowers of Trumpet Honeysuckle while the larvae of Spring Azure Butterflies, Hummingbird Clearwing Moths and Snowberry Clearwing Moths can be found dining on the blue-green semi-evergreen foliage.
Trees and Shrubs – A discussion of plants for caterpillars would be incomplete without mention of the valuable native trees and shrubs that support caterpillars of many butterfly and moth species. As you plan your insect-friendly landscapes do not forget to include trees and shrubs as larval host plants. Some of the most valuable to a large variety of insect species include: Quercus sp., Prunus serotina, Salix sp., Lindera bezoin, and Rhus sp.
We plant natives to support wildlife. We know in many cases there needs to be a balance between aesthetics and faunal value. This means we plant natives to support the complete life cycles of the wildlife we value and we accept holes chewed in leaves, We know that eventually our reward for tolerating some imperfections will be a glorious display of vibrant butterflies, dusky moths and warbling songbirds.