Spiraea alba
Rose family (Rosaceae)

Description: This shrub is 2-6' tall and sparingly branched. Young branches are green and glabrous, but they become smooth, brown, and woody with age. Alternate leaves (up to 3" long and " across) occur along the young branches of this shrub; they are densely distributed along these branches. The leaves are narrowly ovate, sharply serrated, pinnately veined, and glabrous (rarely sparsely hairy underneath); they have short petioles. The upper side of each leaf is medium green, while its lower side is pale green. The branches terminate in panicles of flowers about 2-6" long; these panicles are oblongoid to pyramidal in shape. The stalks of each panicle are light green and either glabrous or pubescent. Each flower is about " across, consisting of 5 white petals, 5 light green sepals, 5 light green pistils, and numerous stamens (20 or more). The petals are much longer than the sepals, while the filaments of the stamens are much longer than the styles of the pistils. Where the nectaries of each flower are located, there is a narrow ring-like structure that surrounds the 5 pistils in the center of the flower; this floral structure is pink, orange, or yellow. The blooming period occurs from mid- to late summer and lasts about 1-2 months. Each flower is replaced by a cluster of 5 hairless follicles with short beaks; each follicle opens along one side to release its seeds (about 2-5 per follicle). The leaves of this shrub are deciduous and its root system is woody.

Cultivation: Meadowsweet prefers full sun, wet to moist conditions, and soil containing abundant organic material (including peat). Standing water is tolerated if it is temporary.

Range & Habitat: The native Meadowsweet is occasional in northern Illinois, uncommon in central Illinois, and rare or absent in the southern section of the state (see Distribution Map). It prefers glaciated areas of the state that are sunny and poorly drained. Habitats include wet prairies, low areas along streams, edges of marshes, bogs, and ditches.

Faunal Associations: The flowers produce nectar and pollen; they attract bumblebees, various other bees, wasps, adult long-horned beetles (Cerambycidae), and the moth Ctenucha virginica (Virginia Ctenucha). The caterpillars of the butterfly Celastrina argiolus (Spring Azure) feed on the flowers and buds of Meadowsweet. The caterpillars of several moths also feed on Meadowsweet and other Spiraea spp. (usually the leaves); see the Moth Table for a listing of these species. The leaf beetle Tricholochmaea spiraeae (a.k.a. Pyrrhalta spiraeae) is a specialist feeder of Meadowsweet (both Spiraea alba & Spiraea latifolia), while the larvae of several gall gnats also rely on these shrubs as a source of food and habitation; see the Gall Gnat Table for a listing of these species and their symptomatology. Among vertebrate animals, the Ruffed Grouse and Greater Prairie Chicken eat the flowerbuds of Meadowsweet; the latter gamebird also eats the seeds during the fall and winter. White-Tailed Deer often browse the upper leaves and twigs, while the Cottontail Rabbit occasionally browses the lower leaves and twigs.

Photographic Location: A seasonal wetland at Judge Webber Park in Urbana, Illinois.

Comments: This is one of two native Spiraea spp. in Illinois. The other species, Spiraea tomentosa (Steeplebush), is a more hairy shrub with pink flowers. In Illinois, it is less common than Meadowsweet and prefers sandy wetlands. Another species, Spiraea latifolia (Eastern Meadowsweet), is found in wetlands further to the east. This species is very similar in appearance to Spiraea alba (Meadowsweet), except it has leaves that are more broad. Sometimes Eastern Meadowsweet is considered a variety of Meadowsweet and referred to as Spiraea alba latifolia. The showy Spiraea spp. that are commonly cultivated as landscape plants have been introduced from the Old World. They rarely escape from cultivation and are not often found in natural habitats.