What Do Caterpillars Eat? Host Plants

sweet fennel swallowtail caterpillar

The plants that caterpillars eat are called host plants while the plants that adult butterflies eat (actually they “drink” nectar from the flowers) are called nectar plants. Each species of butterflies has specific host plants on which the adult butterflies lay their eggs.

Listed below are several popular butterfly species and the host plants that their caterpillars eat. The butterflies are particular about where they lay eggs because their caterpillars must have that distinct host plant to survive. In other words, the caterpillar will not eat if it does not have access to one of its specific host plants and will die.

Some caterpillars are so picky that there is only one plant type that will support them. Fortunately, many caterpillars will eat from more than one plant type.

The Best Host Plant for Caterpillars to Eat?

Giant Swallowtail caterpillar with osmeterium
Giant Swallowtail caterpillar on one of its host plants, Common Rue

You may find that in one region of the country the butterfly caterpillars may prefer to eat a specific variety of their host plant. Likewise, they may prefer a different host plant in other regions. In addition, the preference can vary from garden to garden. This may be due to changes in soil types, pH, etc.

Therefore, determining the “best” host plant to attract a certain butterfly is not always easy.  Offer a few different plants in the host group for a specific butterfly. This will increase your chances of attracting that butterfly to your garden.

zebra longwing caterpillar
The Zebra Longwing butterfly/caterpillar is found in the deep south. The spikes are soft and do not hurt
Source: DeadEyeArrow reproduced under
Creative Commons

If you are raising caterpillars and you happen to run out of caterpillar food, you should be successful in changing their food source. As long as it is in their group of host plants, they should eat the leaves. Fortunately, many caterpillars will easily eat from several food plants within their normal host plants. Even though they will have preferences, they will eat what is available within their host group.  The table below can help you find something to feed your caterpillar if you happen to run out of food!

Joyful Butterfly sells several of these plants and seeds. All of our plants and seeds are safe for caterpillars and butterflies. Some of the plants listed below can also be found in local nurseries.  Be sure to ask about pesticide use if you are planning to buy them to feed caterpillars. Pesticides are very common in nurseries unless they cater specifically to organics/wildlife.

What Caterpillars Eat:

BUTTERFLY SPECIESHOST PLANTS
Anise Swallowtailanise, parsley, carrot, dill, fennel, rue
Eastern Black Swallowtail_________anise, parsley, carrot, dill, fennel, rue, Golden Alexanders (Zizia aurea)
Giant Swallowtailcitrus, hop tree, prickly ash, rue
Pipevine SwallowtailDutchman’s Pipe, pipevines (not the exotics), Virginia snakeroot
Spicebush Swallowtailspicebush (primarily), sassafras, camphor tree (Cinnamomum camphora), various bays (Persea spp.)
Eastern Tiger Swallowtailmany broadleaf trees and shrubs, lilac, willow, birch, tuliptree, cherry
Zebra Swallowtailpawpaw
MonarchMilkweed (Asclepias)
Viceroywillow, poplar, aspen, apple, cherry, plum
Red-Spotted Purpleapple, aspen, cherry, hawthorn, hornbeam, poplar, willow
Great Spangled Fritillaryviolets, (Viola tricolor)
Variegated FritillaryViolets, (Viola tricolor), pansies, stonecrops, passionflowers (Passiflora incarnata), plantains
Meadow Fritillaryviolets (Viola sororia, Viola pallens)
Mourning Cloakelm, poplar, willow
Question Markelm, hackberry, hop, nettle, false nettle (Boehmeria cylindrica)
Green Commarhododendron, azalea, birch, willow
Red Admiralnettle, false nettle (Boehmeria cylindrica), hop
Painted Ladymembers of the mallow family, Malva sylvestris, Tree mallow (Lavatera), thistles, goosefoots
American Painted Ladydaisies, everlastings, other composites, Hollyhock (Alcea rosea), Pearly Everlastings
Buckeyeplantain, snapdragon, stonecrop, verbena, (Verbena stricta), other garden flowers
Baltimore Checkerspotturtlehead (primarily), false foxglove, plantain, white ash
Pearl Crescentasters, New England Aster (A. novae-angliae)
Great Purple Hairstreakmistletoes
Gray Hairstreakcotton, mallows, strawberry, legumes, mints
American Coppersheep sorrel, curly dock, mountain sorrel
Tailed Blueclovers, beans, peas
Spring Azureblueberry, California lilac, dogwoods, meadowsweet, viburnums
Cloudless SulphurSenna marilandica, senna, clovers, other legumes
Clouded Sulphurclovers and other legumes, Wild Blue Indigo (Baptisia australis)
Orange Sulphurwhite clover, alfalfa, vetch, lupine, Wild Blue Indigo (Baptisia australis)
Dogfacefalse indigo, clovers, lupine, vetch, leadplant
Checkered Whitecrucifers, Cleome
Cabbage WhiteCabbage, Mustards, other crucifers, nasturtium
Zebra Longwingpassionflowers, Passiflora incarnata
Gulf Fritillarypassionflowers, Passiflora incarnata, Passiflora caerulea
Malachiteyerba papagayo

Popular Butterflies and Their Host Plants

Monarch butterflies and Black Swallowtail butterflies (Anise Swallowtail butterflies in the West) are popular, easy, and beautiful caterpillars/butterflies to raise indoors or outside. They are found throughout most of the US and beyond. If you are new to raising butterflies, consider starting with what these caterpillars eat. For instance, Parsley (curled or flat leaf) and common rue are my local favorites for Black Swallowtail caterpillars. Purple milkweed (Asclepias purpurascens) is my current favorite for Monarch caterpillar.

These plants are attractive and well behaved in a garden setting. As a bonus, Milkweed has the advantage of being a popular nectar plant as well. Parsley can be found in most local garden centers, but ask about pesticides. Remember, If used on the plants, it will kill the caterpillars. The common rue plant is a perennial and will start easily from seeds or cuttings.

Many people already have nectar plants in their gardens that attract some butterflies. By adding what the caterpillars eat, you will greatly increase the number and duration of butterflies. In addition to watching butterflies, this gives you the opportunity to watch the whole amazing life cycle of a butterfly in your own garden!