Spiraea thunbergii Siebold ex Blume

Thunberg's Meadowsweet

© SRTurner

Family - Rosaceae

Habit - Perennial shrub, 1.0-1.5 m tall, typically somewhat arching, deciduous.

Stems - Ascending or somewhat arching, to 1.5 m, reddish-brown, sparsely pubescent.

	Stem.
© SRTurner

Leaves - Alternate, simple, sessile or nearly so, typically borne in fascicles. Blades oblong to lanceolate, shallowly toothed in distal half, pale green, glabrous or nearly so. Leaves develop after flowering.

	Stem and nodes.
© SRTurner

	Stem and leaf fascicles.
© SRTurner

	Leaf adaxial.
© SRTurner

	Leaf abaxial.
© SRTurner

Inflorescences - Open and somewhat arching, with flowers typically borne in fascicles.

	Inflorescence.
© SRTurner

	Inflorescence branch.
© SRTurner

	Inflorescence branch.
© SRTurner

Flowers - Sepals 5, spreading to ascending at flowering, triangular, persistent at fruiting. Petals 5, broadly obovate to nearly circular, white (pink in some cultivars). Stamens 15 to numerous. Pistils 5, free. Ovary superior, with 1 locule and 2 to several ovules. Style 1 per pistil, persistent, the stigma more or less capitate.

	Flowers.
© SRTurner

	Sepals.
© SRTurner

Fruits - Follicles, elliptic-ovate in outline, tapered to an erect beak at the tip, glabrous, tan to brown and leathery to papery at maturity, dehiscing along the inner suture and also partially along the outer (dorsal) suture, 1-4-seeded. Seeds 1.5-2.5 mm long, narrowly ellipsoid, the surface with faint longitudinal lines or a fine network of slender ridges and quadrangular pits, yellowish to reddish brown.

	Immature fruits.
© SRTurner

Flowering - April.

Habitat - Open areas to partial shade, old homesites.

Origin - Native to Asia.

Lookalikes - Other species of Spiraea.

Other info. - This attractive species is rarely if ever found growing wild in Missouri. The plant photographed above was a single specimen of uncertain provenance, possibly representing a garden escape. Plants in the genus are common in the horticultural trade and are popular landscaping choices. Although individual flowers are small, they are often borne in great profusion.

Photographs taken at Shaw Nature Reserve, Franklin County, MO, 3-17-2025 through 4-17-2025 (SRTurner).