|Light requirements:||full sun|
Spiraea thunbergii ('Thunberg's meadowsweet, Baby's Breath Spiraea, or Thunberg's Spiraea) is a plant in the rose family, native to Japan and China, and a popular landscape shrub in southeastern U.S.
Spiraea thunbergii is a small, long-lived shrub with thin, flexible stems. The flowers are white, borne in early spring (late March to early April) and late fall. It reaches a height of 1.5-1.8 meters (4-6 ft) and is about as wide. The alternate, simple, almost linear leaves are semideciduous.
Grows and flowers best in full sun.
This species forms an interspecific hybrid with Spiraea japonica L. fil. 
In the horticultural trade one can obtain several varieties of Spiraea thunbergii, such as 'Mt Fuji' (white flowers), 'Ogon' (bright yellow flowers), 'Mellow yellow' and 'Fugino pink'
This plant produces phytotoxic cis-cinnamoyl glucosides and cis-cinnamic acid  The plant-growth inhibition characteristics can be used against diverse species as lettuce (Lactuca saliva), pigweed (Amaranthus retroflexus), red clover (Trifolium pratense), timothy (Phleum pratense), and bok choy (Brassica rapa var chinensis). The characteristics of these natural chemicals indicate a potential role of cis-cinnamic acid and its glucosides as allelochemicals (chemicals, released from plants, that cause an interaction between plants and other living organisms) for use as plant growth regulators and weed suppression in agricultural fields and in natural ecosystems. 
Prune in spring just after flowers. Can be grown as a cutback shrub, or trimmed as a hedge.
Propagated by stem or root cuttings.
Pests and Diseases
|Wikiversity is collecting bloom time data for Spiraea thunbergii on the Bloom Clock|
- Horticultural Research (Japan)(2006): Floral Characteristics of Interspecific Hybrids between Spiraea thunbergii Sieb. ex Blume. and S. japonica L. fil.
- Phytochemistry. 2004 Mar., v. 65, no. 6 p. 731-739
- Journal of chemical ecology 2005, vol. 31, no3, pp. 591-601