If butterflies could talk, they’d tell us not all plants are equal. Luckily, researchers are closely observing them and how they interact with plants. First off, they found butterflies look for beacons of color – especially red, yellow, orange, pink and purple. Next, they search for safe places to land and easy food access. Think flowers with flat-topped landing pads and short flower tubes making it easy to obtain nectar. To sustain them on their journey, they’re seeking quality food (nectar) and water. And when they’re ready to lay eggs, they’re searching for host plants to provide food for their emerging young caterpillars. Finally, they need a safe, pesticide-free place for their larvae to eat and grow.
At Mt. Cuba Center’s Trial Gardens in Delaware, scientists evaluated dozens of plant cultivars from coneflowers to garden phlox to see which ones gain the most butterfly visits. Read on for our favorite nectar and host plants from this trial and our own experiences.
Coneflowers (Echinacea): These native flowers are super popular for good reasons. They’re tough as nails, bloom through the summer and tolerate drought conditions. While many of the new cultivars are super cool, studies show butterflies prefer the classic single blooms versus the funkier pompom and double varieties. Try the dwarf ‘Pica Bella,’ the colorful ‘Cheyenne Spirit,’ the top-performing Sombrero series, ‘Kismet Raspberry,’ ‘Snow Cone’ and the native Echinacea pallida -- a host plant for the silvery checkerspot.
Bee Balm (Monarda): From the mint family, bee balm is a nectar source for butterflies especially swallowtails and silver-spotted skippers. Today’s cultivars are more mildew and disease resistant. Plus, their colors range from white and red to purple and pinks, with sizes from dwarf (12”) to four feet. Top performers include ‘On Parade,’ ‘Grand Marshall’ plus the Balmy and Sugar Buzz series.
Garden Phlox (Phlox paniculata): Phlox weave color through the late summer garden. At the Mt. Cuba trial garden, ‘Jeanna’ – a classic native selection -- was a hit with 518 butterfly visits. New hybrids are more mildew resistant, reblooming and more compact. Try ‘Uptown Girl,’ the Opening Act series and the Fashionably Early series.
Tall Verbena (Verbena bonariensis): This tall purple Brazilian variety is a popular nectar source with butterflies. We love how its tall, willowy stems add a hazy see-through effect to a perennial border. The plants are hardy to zone 7, so we treat them as annuals and replant each year.
Lantana (Lantana camara): These nectar-rich annuals bring butterflies in droves. They provide non-stop color in red, orange, yellow, white, pink, and purple and even offer a slight, spicy floral fragrance. Try new varieties like the ‘Sunrise Rose,’ and Bandana and Bloomify series. They’re incredibly heat tolerant and perfect for containers and hanging baskets.
Stokes Aster (Stokesia laevis): This drought-tolerant native perennial features large purple blooms in mid-summer. The flowers close at night and reopen with the morning sun ready to greet butterflies and hummingbirds. Plant in well-drained soil and deadhead for extended blooms.
Ironweed (Vernonia): Climbing 3-7 feet, this purple-flowered, fall-blooming perennial adds plenty of height to the back of the border. Combine ironweed with ornamental grasses. Try compact varieties (like ‘Summer Surrender,’ ‘Iron Butterfly’ and ‘Summer Swan Song’ that reach 3 to 4 feet.
Oregano (Origanum): Butterflies are herb aficionados, and oregano is one favorite. Plant wild marjoram (Origanum vulgare) as well as purple oreganos (Origanum laevigatum) ‘Hopley’s’ and ‘Herrenhausen’ for an irresistible nectar source. Also try ‘Aureum’ with golden leaves and pink flowers.
Zinnia (Zinnia): These hard-working annuals are butterfly magnets. Plant the Zahara or Profusion series along a sidewalk or add the taller Benary’s and State Fair varieties to a cutting garden. The bigger-flowered varieties serve as landing pads for nectar-seeking butterflies. Red and hot pink flowers get the biggest draw.
Hardy Hibiscus (Hibiscus moscheutos): These hardy perennials attract butterflies with their giant, tropical-looking flowers. In late summer, these impressive four-foot plants emerge and bloom with flowers. Learn more about this favorite in our Hardy Hibiscus post.
Sedum: While sedums are beloved for their cool succulent leaves, butterflies are drawn to their late-summer flower clusters. They offer a great nectar source through fall. Try ‘Dazzleberry’ with hot pink blooms and purple foliage, ‘Lime Zinger’ with apple-green leaves and pink flowers or ‘Autumn Fire’ with deep red flowers.
Asters (Symphyotrichum): These signature fall-flowering perennials are a must-have for foraging butterflies. They fill a nectar gap late in the season when few other plants are in bloom. Asters are also a host plant for silvery checkerspot and pearl crescent. Try New England aster (Symphyotrichum novae-anglia), Aromatic aster (Symphyotrichum oblongifolium) and the Kickin aster cultivars.
Beyond nectar, butterflies need host plants to provide food and cover for their young. Here are a few to add to your garden.
Milkweed (Asclepias): For monarchs, milkweed is a must-have. Monarch caterpillars exclusively feed on milkweed leaves before they form chrysalises. Plant common milkweed (Asclepias syriaca), swamp milkweed (A. incarnata), and butterflyweed (A. tuberosa).
Passionflower (Passiflora): This vigorous perennial vine features intricate flowers in purple and white. The name was given by 14th century Roman Catholic priests for plant’s parts that symbolize elements of Christ’s crucifixion also known as “passion.” Passionflower is a host plant for fritillaries.
Hollyhock (Alcea rossea): These cottage garden biennials are host plants for painted lady caterpillars. Varieties range from single to double flowers and a host of colors. Plant them along a wall or fence to support their towering spires.
Pearly Everlasting (Anaphalis margaritaceae) – Part of the aster family, this North American native grows three feet and features silver-gray foliage with white rounded flowers. It is a host for painted lady and American lady caterpillars.
Bronze fennel (Foeniculum vulgare): Plant this aromatic perennial herb to host Eastern black swallowtail caterpillars. We love its wispy dark purple foliage and bright yellow flowers in the landscape. Enjoy some of its licorice-flavored leaves before the caterpillars do.
Black-eyed Susan (Rudbeckia hirta): These cheery perennials are the larval host to bordered patch, gorgone checkerspot and silvery checkerspot butterflies. They thrive in full sun and are heat tolerant.
Ornamental grasses: Ornamental grasses also provide habitat for young caterpillars. Carex pensylvanica supports 36 species of caterpillars. Little bluestem and switchgrass are hosts for many skipper caterpillars.
Trees and shrubs: Many are surprised to learn butterflies also turn to trees and shrubs as hosts for their young. Add some of these favorites to host various butterflies in your backyard: oak trees (Horace’s duskywing and banded hairstreak), willows (Western swallowtail, viceroy, mourning cloak), pawpaw (zebra swallowtail), black elderberry (spring azure), spicebush (spicebush swallowtail) and chokeberry (Weidemeyer’s admiral, red-spotted purple, spring azure and tiger swallowtail).