Spireas are divided into two main groups based on flowering time: spring-flowering and summer-flowering.
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| Spireas are divided into two main groups based on flowering. |
Spring-flowering species: These shrubs bloom on the previous year's growth. Their flowers are usually white, gathered in umbels or corymbs, and bloom in May and June.
Spiraea × cinerea 'Grefsheim' is a popular hybrid with graceful, arching shoots and double, snow-white flowers. Spiraea × vanhouttei is a large, spreading shrub with cascading branches covered in white flowers. Spiraea arguta is one of the earliest and most profusely blooming species with drooping branches. Spiraea nipponica is a dense shrub with dark green foliage and white inflorescences (the 'Snowmound' cultivar is well-known).








