3. Spiraea japonica L. f.

Map 2529

Plants shrubs, 0.5–1.5 m tall. Twigs reddish brown to grayish brown with scattered, small, dark lenticels, somewhat angular, minutely hairy toward the tip when young, sometimes glabrous or nearly so at maturity. Leaves sessile or short-petiolate. Leaf blades 6–15 cm long, lanceolate to narrowly ovate, angled at the base, tapered to a sharply pointed tip, the margins finely and sharply toothed, the surfaces glabrous or nearly so. Inflorescences terminal panicles of numerous flowers, wider than long, more or less flat-topped to broadly dome-shaped. Hypanthia 1.5–2.0 mm wide, cup-shaped, minutely hairy. Sepals 1.0–1.5 mm long, triangular, sharply pointed at the tip. Corollas not doubled, with 5 petals (doubled in some cultivated forms). Petals 1.8–2.5 mm long, pink. Ovaries glabrous. Fruits 2.5–3.0 mm long, glabrous. 2n=18. June–August.

Introduced, uncommon, (native of Japan, introduced widely in the eastern U.S. west to Illinois, Missouri, and Alabama). Seepy banks of streams.

For many years, Stan Hudson observed a solitary, mature shrub persisting from an old planting near a former sawmill in Wayne County, but this individual never reproduced itself by seed or vegetatively. However, in 2001 Bill Summers discovered a large population of reproducing shrubs scattered on the seepy banks of a stream in Shannon County.