Propagation of Spiraea

By Derek Devine

Abstract

The purpose of this web page is to give information about the propagation, use, location, and culture of Spiraeas.Also, I will include some examples of the many cultivars of Spiraeas.Since most spiraeas are native to central and East Asia, I will focus on the Japanese Spiraea—Spiraea japonica.

 
 
 
spiraea
DEFINITION:any plant of the genus Spiraea, Northern Hemisphere deciduous shrubs of the family Rosaceae (rose family). Most are indigenous to central and E Asia, whence come most of the popular ornamental species, e.g., the bridal wreath (S. x prunifolia), native to Japan, and its similar hybrid S. vanhouttei. In these species the fragrant, spirelike flower clusters typical of the genus are borne on long, arching branches. Spiraeas native to North America include the hardhack, or steeplebush (S. tomentosa), a local source of astringent and tonic, and the meadowsweets (several species). The name meadowsweet is also applied to the related genus Filipendula, tall, hardy perennials (also often cultivated) formerly classified as Spiraea because of the similar showy blossoms. Filipendula includes the Eurasian dropwort (F. hexapetala), the queen of the meadow (F. ulmaria), now naturalized in the United States, and the North American queen of the prairie (F. rubra). Spiraeas are classified in the division Magnoliophyta, class Magnoliopsida, order Rosales, family Rosaceae.

(The Columbia Encyclopedia, Sixth Edition)


 

Japanese Spiraea

Description


Japanese spiraea is an erect, multi-stemmed deciduous shrub that gets 2-6' tall with a similar spread. The slender reddish brown stems may be hairy or glabrous. They bear alternate ovate leaves that are 1-3" long and usually paler on their undersides. The leaves have toothed margins, wedge-shaped bases, and pointed tips. Leaf color varies from chartreuse to blue-green to bronze, orange, red, or burgundy with variety and season. Flat-topped clusters (corymbs, to be technical) of pink flowers are displayed at the tips of the wiry branches. In the most common forms, the pink color results from a mix of light and dark pink that gives the blossom a pixilated appearance. Small capsules hold seeds about 1/10 inch long. The species Spiraea japonica is an upright shrub, 4-6' tall. 

Cultivars


 
Bumalda spirea (cv. 'Bumalda'),
Spreading shrub, only 2-3' tall
'Alpina' or Daphne spirea
Low, dense, spreading, slow-growing groundcover type with pink flowers and small bluish-green leaves that turn red and orange in fall;
'Magic Carpet'
Compact shrub that has dark pink flowers and leaves that emerge red, mature to bronze, then change to deep red in the fall;
'Neon Flash'
Rosy-red-flowered 4' shrub with leaves that start out reddish and retain a purplish tinge;
'Shibori' or peppermint stick spirea
Low mound-shaped shrub that bears multi-colored white, pink, and red flowers all summer;
'Anthony Waterer'
2-3' bush with maroon-tinged foliage and reddish-pink flowers
‘Dolchica’
2' shrub with bright pink flowers and deeply incised leaves that emerge purple
‘Froebelii'
Especially cold-tolerant (to Zone 3) variety that has purplish new growth and produces rosy-pink flowers off-and-on through the early summer
'Goldmound'
Compact 1-3' pink-flowered shrub with creamy chartreuse-yellow foliage that turns rusty gold with red tips in the fall.

Location
 

Not surprisingly, Japanese Spiraea comes from Japan. It also is considered native to Korea and China. It has naturalized in North America from New England south through the Appalachians into Tennessee and Georgia, and west to Indiana. Japanese Spiraea usually grows along stream bottoms and on seepage slopes, but readily invades forest edges and openings, old fields, roadsides, and utility rights-of-way.

Culture


Japanese spiraea will grow in a wide variety of soils, including those on the alkaline side, but it prefers a rich, moist loam. These shrubs appreciate manure and thrive on organic mulch. Since they bloom on the current season's growth, Japanese Spiraea should be pruned in winter or early spring. They can be cut all the way to the ground. After the flowers fade, shear them off to stimulate a second flush of growth and more flowers. Mowing will control expansion of a planting, but the stems will re-sprout, so repeated cutting will be a long-term necessity. Spiraeas may suffer minor damage from a variety of pests and diseases, but they are not prone to any major problems. Aphids occasionally are a nuisance in the spring.

Propagation
Japanese spiraea reproduces aggressively in the wild. A single plant can produce hundreds of seeds that remain viable and persist in the soil for many years. Typically the seeds are dispersed by water and deposited along stream banks. They also are distributed in fill dirt. In cultivation, sucker division or softwood cuttings rooted under mist in a warm place during the summer usually propagate Japanese Spiraea. Hardwood cuttings can be rooted outdoors in the fall. Pegging down a branch in the spring, and potting it up in the fall also may layer this plant. Spiraeas are easy to transplant. Fall is the best time to divide plants, but spring and fall are both good for setting out new ones.

Usage


Tall forms are grown as hedges, low screens, or foundation shrubs. Low-growing forms are used as groundcovers or in borders.

References

http://www.floridata.com/ref/s/spir_jap.cfm
http://www.msue.msu.edu/msue/imp/mod03/01702052.html#visuals