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Swallowtail Butterfly Gardening

Swallowtail Butterfly Gardening Featured Image

Gardeners tend to have a thing for swallowtail butterflies.  Likewise, swallowtails tend to have a thing for certain plants – and certain gardens. The more you incorporate their favorites into your garden, the more they will favor you with their flighty visits.

Adult swallowtails of all species (including the half-dozen or so species native to eastern North America) share similar tastes in nectar.  A border brimming with coneflowers and sages and butterfly weeds and their relatives will have them all aflutter, as will a planting of shrubby favorites such as rhododendrons and buddleias.  Swallowtail caterpillars, on the other hand, are much fussier eaters, with each species following a specialized diet restricted to a narrow menu of plants.  As a result, swallowtails are particularly keen on gardens that include their favorite larval foods.

Most swallowtail caterpillars confine their munching to species from one or two plant families.  Some swallowtail species thrive on both introduced and indigenous plants, whereas others require natives-only fare to thrive.  Know their preferred larval food sources, and you’ll know what to plant in your yard to transform it into a swallowtail haven.   You’ll also know which plants to examine for the large colorful caterpillars, which in their early stages resemble animated bird droppings.  Some leaf damage may also be noticeable, but it’s a modest price to pay to become the neighborhood’s most desirable swallowtail destination.

Swallowtail Caterpillar Host Plants

1. Easter Tiger Swallowtail

Eastern tiger swallowtail butterfly feeding on pentas
Eastern tiger swallowtail butterfly feeding on pentas. (Image by Jessie Keith)

Many native and exotic trees and shrubs from the olive, rose, laurel, birch, and magnolia families host the large green caterpillars of tiger swallowtail, which sport two prominent eye-spots.  Before pupating, the caterpillars turn from green to brown. Tulip tree (Liriodendron tulipifera), lilacs (Syringa spp.), river birch (Betula nigra), and sassafras (Sassafras albidum) are among the outstanding ornamental plants on the menu, as are:

Eastern tiger swallowtail caterpillar before pupation. (Image by Scott Robinson)
Eastern tiger swallowtail caterpillar before pupation. (Image by Scott Robinson)

Sweet bay magnolia (Magnolia virginiana).  Native to eastern North America, this small, elegant, gray-barked tree has glossy-green, deciduous or evergreen leaves with silvery undersides.  Scatterings of cupped, sweet-scented white flowers sporadically appear from late spring through summer.


Fringe tree (Chionanthus virginicus).  Clouds of fragrant, fleecy white flowers veil the spreading branches of this large shrub or small tree in late spring.  Conspicuous blue fruits ripen in late summer on some plants (particularly if a pollenizing companion fringetree is nearby).

2. Eastern Black Swallowtail

Female eastern black swallowtail
Female eastern black swallowtail lays her eggs on plants in the parsley family.

Showy, yellow-and-black-banded caterpillars feed almost exclusively on plants from the parsley family, including dill (Anethum graveolens), parsley (Petroselinum crispum), carrot (Daucus carota ssp. sativus), and fennel (Foeniculum vulgare).   Bronze-leaved forms of fennel are especially effective ornamentals, their dark, filigreed leaves making a smoky contrast to bright-flowered annuals and perennials. 

Also outstanding for foliage effect are the various species of Peucedanum such as giant milk parsley (Peucedanum verticillare).  This short-lived perennial forms large lush hummocks of deeply divided foliage, which give rise to towering, purple-stemmed sprays of lacy white flower clusters.  Most Peucedanum expire soon after flowering, but they usually self-sow (so be sure to leave some seed heads!).

3. Spicebush Swallowtail

Spicebush swallowtail butterfly
Spicebush swallowtail larvae feed just on spicebush. (Image by Magnus Manske)

A dark-hued butterfly that somewhat resembles black swallowtail, spicebush swallowtail is one of several reasons to grow the shrub after which it’s named.  So, too, are the boldly eye-spotted, green to orange-yellow larvae that browse spicebush’s fruity-scented foliage in summer.   One of the earliest-blooming native plants, spicebush (Lindera benzoin) decks its branches with tufts of acid-yellow flowers

Spicebush swallowtail caterpillar (Image by Greg Schechter)
Spicebush swallowtail caterpillar (Image by Greg Schechter)

in late winter and early spring, before the leaves emerge.   Bright red fruits and brilliant yellow fall foliage bring the growing season to a colorful close. Spicebush swallowtail’s other favorite host is sassafras – the only eastern North American representative of the laurel family (Lauraceae) other than Lindera benzoin.

4. Pipevine Swallowtail

Pipevine swallowtail butterfly
The pipevine swallowtail has showy blue lower wings.
A pipevine swallowtail caterpillar feeding on pipevine. (Image by Jessie Keith)
A pipevine swallowtail caterpillar feeding on pipevine. (Image by Jessie Keith)

If outlandish black caterpillars with orange spikes and centipede-like “legs” appear on your Dutchman’s pipe vine (Aristolochia spp.), you have the honor of a visit from this singular swallowtail species.  With luck, you’ll also witness the adults, whose blue, iridescent wings are among the showiest in the butterfly tribe.  The larvae thrive only on North American species of Aristolochia, dwindling away if raised on exotic Dutchman’s pipes such as Aristolochia elegans.  

Two twining North American natives – Aristolochia macrophylla and A. tomentosa –make excellent climbers for locations where their wide-ranging roots have room to spread (both are hardy from USDA zones 5 to 9).  Their rapidly ascending stems with heart-shaped leaves emerge from the ground in spring and lengthen to 20 or 30 feet within a few weeks.  Curious, contorted, tubular flowers with flared tips appear in the leaf axils in early summer.  Most other North American Aristolochia species are lower-growing perennials that spread underground to form large clumps.  Virginia snakeroot (Aristolochia serpentaria) functions nicely as a deciduous ground cover for informal garden areas in sun to light shade.

5. Eastern Giant Swallowtail

Eastern giant swallowtail butterfly
Citrus is the favorite host plant of eastern giant swallowtail.

Native or exotic species from the citrus and rue family (Rutaceae) entice this enormous, black, yellow-banded butterfly, whose wingspan can reach 6 inches.  Gardens that are too cold for the likes of lemons (Citrus limon) and oranges (Citrus aurantiaca) can opt instead for one of the several cold-hardy Rutaceae species that host the blotchy, black and white larvae.  These include hop tree (Ptelea trifoliata), a medium to large shrub from central and eastern North America with handsome, three-parted leaves and small, fragrant, late-spring flowers.  Rounded, wafer-like fruits develop in late summer.

Larva on leaf

Its cultivar ‘Aurea’ – with glossy, chartreuse-yellow leaves – is one of the most striking foliage plants for temperate gardens.   Swallowtail hosts for the perennial border include gas plant (Dictamnus albus), which bears showy spires of white or purple flowers in late spring on bushy, 3-foot-tall mounds of leathery, rich green foliage.  Native to Eurasia, it lives to 50 years or more in gardens.  Warning: contact with plants in the rue family can trigger severe dermatitis in susceptible individuals, although such cases are rare.
[Click here to get great butterfly garden designs!]

Gardening Tips for Dog Owners

Gardening Tips for Dog Owners Featured Image
Some plants are more attractive to dogs than others, so choose canine-proof plantings.

You love your dog.  You love your garden.  Sometimes, though, your dog and garden just don’t get along, and it is harder to feel the love. The dog follows its instincts and digs, pulls up plants, romps over delicate specimens, and relieves himself in the wrong places.  You follow your instincts and get frustrated.

What can you do?

As with all things related to gardening, a little planning can prevent a lot of mayhem. Make a few adjustments to accommodate dog and animal priorities, and you can transform the garden into a place where both the resident gardener and the resident canine/s can feel comfortable.

Paths for Dogs

Create garden paths and raised bed borders to keep straying humans and dogs out of garden beds and borders. Paved walkways are the best way to prevent muddy paws, but fine gravel or mulch will also work.  Avoid using cocoa bean mulch along the paths or in beds because it is toxic to dogs, and they like to eat it.

Training

Little dog digging in the garden
Dogs are diggers, so train them early to avoid garden digging.

Famed dog trainer, Barbara Woodhouse, famously said, “Dogs aren’t born knowing what or what not to do; they only learn like children.”  Invest in proper training for your four-legged “child” so that the two of you can work together to set boundaries—literally and figuratively—for garden behavior.  Training works best when you start on a puppy, but even older dogs can benefit, especially from a skilled trainer.

Training does not have to be expensive.  A wide array of available books, videos, and apps can guide you through gentle, effective ways of training your dog.  No matter what method you choose, the cost of training beats the trouble and expense of repairing your landscape when your furry friend misbehaves.

Planting for Dogs

Dog in between garden borders
Garden borders and paths can make it easier to teach dogs to stay out of beds.

Use tough plants along paths and other canine traffic areas and plant densely, because bare earth invites canine curiosity, mischief, and digging.  Enrich the soil every time you plant by using a quality amendment like Fafard® Garden Manure Blend to encourage thick, leafy growth

Ornamental grasses, compact shrubs, and even sturdy, clump-forming perennials, like big-root geranium (Geranium macrorrhizum), can withstand the occasional trampling or exuberant full-body roll and survive intact.  Low-boundary fencing may also help separate pets from plants.

Avoid planting species and varieties with sharp prickles or spines, and keep toxic plants confined to areas that are off-limits to your dog.  For a list of toxic indoor and outdoor plants, go to the ASPCA website on toxic plants (click here to view) or read our article about the 12 Most Poisonous Plants to Avoid for Kids and Pets.

Dedicated Relief

Dogs also need places to relieve themselves.  If you don’t set aside those dedicated spaces and train the dog to use them, dog waste will harm your lawn and garden. Garden sculptures and other formative yard decor are often attractive to dogs for this purpose. Better they wee on something structural than your plants. Encourage your dogs to mark the right garden areas, and they will return to those spots. Also, keep a pooper scooper handy to keep the lawn clean.

Dog Distractions

Dog among flowers
Keeping dogs distracted and well-exercised will help them lose interest in your beds.

A bored canine is an unhappy canine.  Keep some favorite dog toys in your garden basket or cart and use them to entertain the dog while you plant, weed, and water.  Taking a moment to give your dog a chew toy or throw a ball is much better than watching pup munch the stems of your prize coneflowers and daisies.

Exercise

Author's Dog, Brodie, in a bed of loosestrife
The author’s dog, Brodie, romping in a dense, practically dog-proof bed of loosestrife.

Humans get flabby and unhappy without sufficient exercise, and dogs are no different.  Walk your dog at least forty-five minutes every day, or hire someone else to do so when time is at a premium.  Space permitting; install an enclosed dog run in a corner of your yard, with a latched gate and appropriate shelter for dogs that stay outside periods. A dog that gets regular exercise is less likely to tear up the iris bed or uproot the tomatoes.

One of the most celebrated gardeners and dog lovers was the late English plantsman, Christopher Lloyd, who rarely set foot in his garden at Great Dixter without his faithful dachshunds.  Less famous gardeners agree that canine companionship is good for the psyche and may also deter plant predators like rabbits, groundhogs, and deer.  Even if your dog only wags his tail at rabbits and groundhogs, if he is happy, chances are you will be happy, and the garden will be a better place all the way around.