Diggin’ In: September is prime for Joe-Pye weed and its butterfly friends

September 14, 2015

Joe-Pye weed is major player in the September yard, especially if you want to attract butterflies.

"Joe-Pye weed is a real butterfly magnet," says native plant expert Helen Hamilton of Williamsburg, Va. She is co-author of "Wildflowers and Grasses of Virginia’s Coastal Plain."

Blooming in late summer until frost, Joe-Pye weed (Eutrochium dubium), grows three to 10 feet tall with dense heads of fluffy pinkish flowers that are usually covered with viceroys and other butterflies, bees, beetles and wasps — all in a feeding and pollinating frenzy.

"These plants are a little rough for a formal garden," Hamilton says.

"Long blooming and deer resistant, they can grow very large and are great in a wild garden, or placed to the rear or where a strong accent is needed."

Joe-Pye-weeds are meadow plants; most require full sun, and acidic, rich soil with moist drainage, although some tolerate shade, less moisture, coastal conditions and clay soil. Clump-forming, they will not form extensive drifts, according to Hamilton.

Members of the Aster family, Joe-Pye-weeds have no rays (petals), only disk flowers, and they are tiny, making it easy for small insects to access nectar, she adds. Butterflies, including tiger swallowtails, monarchs and viceroys, also like the flowers.

Three species of Joe-Pye-weed are native to the Coastal Plain, according to Hamilton. The shortest is Coastal Joe-Pye-weed, growing five feet tall. A popular cultivar called Little Joe is only three feet tall and compact, and its mauve-purpose flowers are an excellent choice for a small butterfly garden. Also a good choice for a rain garden, Coastal Joe-Pye-weed grows naturally in bogs, swamps and wet clearings, usually in acidic, poor soils. It grows throughout the Chesapeake Bay watershed, as well as more than 30 states nationwide (not the West Coast or Texas, Louisiana and Florida region).

Purple Joe-Pye weed (E. purpureum) grows to seven feet tall and Hollow-stem Joe-Pye weed (E. fistulosum) can be more 11 feet tall. The flowers of both species are pale pink to purplish, in rounded domes, or loose clusters at the tops of stems.

"The name ‘Joe-Pye weed’ comes from a tale about a North American Indian called Joe Pye, who walked the streets of Boston selling a cure for typhus, using an elixir of this plant to induce profuse sweating, thus breaking the fever — although this story is in some doubt among authors," says Hamilton.

"This plant is also called ‘gravel root’ because it has the ability to remove and to a certain degree dissolve kidney stones or gravel."

Regarding the butterflies they attract, you may wonder, is it a monarch or viceroy?

"They closely resemble each other, but the viceroys are slightly smaller and distinguished by a black band across the hind wings," says Hamilton.

"Also, the two species can be distinguished by their flight patterns — monarchs float, with a ‘flap, flap, glide’ pattern, whereas the viceroy flight is faster and more erratic."

Viceroys overwinter as larvae, rolled up in a leaf of a host plant, willow or poplar, Hamilton adds. They become adults in the spring in about two weeks, after willow or poplar leaves emerge. Spring temperatures control how early the leaves appear and how quickly the caterpillars grow and the chrysalis develops. Adults are seen in wet habitats, along ponds, swamps and rivers, the males perching in late morning and early afternoon, defending territory and looking for females. Mated females deposit a single egg at the tip of a leaf, resembling a gall.

In early spring when few flowers are available, viceroys feed on carrion, dung and decaying fungi. Forming more than one brood per year, later generations feed on late-summer and early-fall plants like Joe-Pye weeds, asters, and goldenrods, all plants with clusters of tiny flowers. From their host plants, the caterpillars sequester salicylic acid in their bodies that makes them taste bitter and upsets the stomachs of predators. Also, the caterpillars and their chrysalis stage resemble bird droppings, which give them natural protection from predators.

Monarch butterflies feed on milkweed plants, ingesting toxic glycosides that are distasteful to predators. The resemblance of the coloration of viceroys to that of monarchs has been suggested as a protective device, but researchers have offered caterpillar bodies without wings of both monarchs and viceroys to birds, which reject both. Butterflies display many color patterns and show a lot of mimicry, but there has been debate as to the explanations for this, according to Hamilton.



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