American Bladdernut

Media
Illustration of American bladdernut leaves, flowers, fruits.
Scientific Name
Staphylea trifolia
Family
Staphyleaceae (bladdernuts)
Description

American bladdernut is a thicket-forming shrub or small tree, with branches near the top, that produces clusters of bell-shaped white flowers in spring and unusual 3-parted air-filled capsules in late summer that turn papery and persist into winter.

Leaves are opposite, compound, with 3 leaflets, each leaflet 1½–2 inches long, egg-shaped or oval, margins sharply and finely toothed, with a pointed tip. Upper surface bright green, hairy on the veins; lower surface slightly paler, hairy. End leaflet stalk ½–1½ inches long, much longer than the stalks of the side leaflets; side leaflets nearly sessile. Leaflet stalks and petioles hairy. The leaves remain green until late in autumn, eventually turning yellowish green.

Bark is grayish brown, smooth on young shrubs and slightly grooved and flaky on older trunks.

Twigs are flexible, smooth, reddish brown to greenish brown, often striped, curved, ascending.

Flowers April–May, in drooping clusters 2–4 inches long on a short stem arising from upper leaf axils (from twigs of the previous year); flowers small, white, bell-shaped, about ¼ inch long; sepals and petals nearly the same length; petals 5, about ¼ inch long, tips blunt; stamens 5, extending beyond the petals.

Fruits in August, persistent until midwinter, solitary or in clusters of 2–5, strongly inflated, bladderlike, drooping capsules 1¼–2½ inches long, 3-lobed, net-veined, green turning to brown, opening at the tip; seeds 1–4, about ¼ inch long, rounded, somewhat flattened, yellowish to grayish brown, hard, shiny.

Similar species: Another shrub, called hop tree, wafer ash, or stinking ash (Ptelea trifoliata), also has trifoliate leaves, but bladdernut has opposite (not alternate) leaves and a relatively long-stalked central leaflet; the flowers and fruits of the two shrubs are quite different.

Common Name Synonyms
Bladder-Nut
Size
Height: to 25 feet; most typically 10–15 feet.
Where To Find
Scattered to common statewide.
Occurs, often in thickets, along banks of streams and rivers, bases and sheltered ledges of bluffs, and rich upland forests in ravines, often on north- to east-facing slopes, especially on limestone or dolomite substrates. It is sometimes planted as an ornamental shrub, especially along borders. If you plant it, keep in mind its habit of suckering from the roots, and allow plenty of room.
This is the only member of the bladdernut family native to Missouri. There are only about 10 species in its genus in the whole Northern Hemisphere; globally, the entire bladdernut family includes only 5 genera and some 27 to 50 species. The bladdernut family comprises shrubs and trees whose flowers are 5-parted, with a superior ovary; the fruits are often inflated. A few are garden ornamentals, including the Colchis or Caucasian bladdernut, and the European bladdernut. One of the bladdernut family’s closer relatives is another small family, the Crossosomataceae (crossosomas), which includes the greasebushes and rockflowers of the American Southwest.
American bladdernut is a fast-growing, hardy native flowering shrub or small tree that works well in rain gardens, naturalized areas, shade gardens, or woodland areas. It prefers moist soils and part to full shade. It has a tendency to sucker and produces dense colonies in the wild. In spring, the drooping clusters of white, tubular flowers are attractive. The curious, air-filled seed capsules, which mature in late summer and often last into early winter, are a fascinating addition to dried flower arrangements.
Trees and shrubs that thrive and survive in low, moist lowland soils play an important role in stabilizing the land along streams and rivers, preventing erosion, reducing the destructiveness of floods, and creating shady, fertile habitat for many other plants and animals.
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About Trees, Shrubs and Woody Vines in Missouri
There are no sharp dividing lines between trees, shrubs, and woody vines, or even between woody and nonwoody plants. “Wood” is a type of tissue made of cellulose and lignin that many plants develop as they mature — whether they are “woody” or not. Trees are woody plants over 13 feet tall with a single trunk. Shrubs are less than 13 feet tall, with multiple stems. Vines require support or else sprawl over the ground.