Are Spirea Evergreen?

Identification

• Spireas are generally hardy in U.S. Department of Agriculture plant hardiness zones 3 through 9. They grow to 6 to 10 feet tall and wide, with many cultivars growing to maximum heights of roughly 3 feet. In cooler climates, all spireas are deciduous and lose their leaves in autumn. In warmer areas, some cultivars retain their leaves during mild winters, only losing their leaves during prolonged cold snaps. These varieties are usually classified as being “semi-evergreen.” Examples include baby's breath spirea (Spiraea thunbergii), hardy in USDA zones 4 through 8, and double bridal wreath spirea (Spiraea cantoniensis), hardy in USDA zones 6 through 9.

Culture

• Full sun usually produces the most abundant blooms, but most varieties of spirea can successfully grow in partial shade. Additionally, spireas adapt to most soil types, but they prefer growing in well-drained, loamy garden soil. They grow well in a range of soil pH levels, although soil requirements vary among cultivars. For example, western spirea (Spiraea douglasii) needs acidic soil while many Japanese spirea (Spiraea japonica) can tolerate slightly alkaline soil. Propagate spireas by taking cuttings and rooting them -- in a container with heat on the bottom for greenwood cuttings or in a cold frame for mature wood cuttings -- or by dividing the plant's root clump in early spring or fall.

Uses

• These pretty shrubs flower profusely during their blooming season, making them a favorite among many gardeners. Fine Gardening recommends using the plants as hedging or in a shrub border or rock garden. The flowering shrubs generally add texture to the landscape and pair well with evergreen shrubs, which form an attractive backdrop when spirea are in full bloom and help detract from their bare branches once they lose their leaves. Use larger cultivars such as baby's breath spirea as a specimen shrub or in small groups.

Plant Care

• Spireas are generally low-maintenance shrubs, although annual pruning helps to keep them looking tidy while encouraging the plants to bloom. Prune up to 1/3 of the plant's tallest and oldest stems as short as 2 to 3 inches above the ground. The New Sunset Western Garden Book recommends pruning shrubby spireas during winter or early spring before the plant begins growing; prune bridal wreath spireas once the plant finishes blooming.