Spireas (Spiraea species) are among the easiest flowering shrubs to grow. These attractive shrubs are fast growing and should be grown in full sun for best flowering. They can, however, tolerate partial shade. Some are spring bloomers; whereas others bloom in the summer. Plant sizes vary by species and cultivar, and they range from 1½ to 8 feet tall. There are many species of spireas (greater than 80), but only the most commonly encountered species and cultivars are included here.
Baby’s breath spirea (S. thunbergii), also called thunberg spirea, is a showy, graceful shrub from 3 to 5 feet high and wide, with many slender, arching branches. The small, narrow, toothed leaves turn orange in late fall. The tiny white flowers are clustered in the axils along the stems in spring. More than any other spirea, it has a feathery appearance. These are some of the earliest bloomers. Prune soon after flowering if needed. For USDA zones 4 to 8.
Vanhoutte spirea (S. x vanhouttei) is a deciduous broadleaf shrub with an arching branch habit that can grow 5 to 8 feet high and spread as much as 7 to 10 feet wide. The Vanhoutte hybrids are crosses of S. trilobata and S. cantoniensis. The small leaves are blue-green in summer with no appreciable fall color. Masses of small, white flower clusters cover the plant in the spring. For USDA zones 3 to 8.
Reeves spirea (S. cantoniensis) is a white, single-flowered shrub with a white bridal wreath growth habit. The straight species is rarely encountered, whereas double-flowered cultivars are more common in South Carolina landscapes. The shrub grows 5 to 6 feet tall. In the Upper South the small green leaves may turn red in fall. In the Deep South they remain on the plant without changing color. Prune after flowering if needed. For USDA zones 5 to 8.
Bridal wreath spirea (S. prunifolia) is an early blooming, deciduous shrub with white, double flowers that appear before the foliage in the spring. This spirea grows to about 6 feet tall and wide. Prune, if necessary, soon after flowering. Fall color is red to orange. These are often found at old home sites and are hardy from USDA zones 5 to 8. Other species of spirea, such as the Vanhoutte spirea, are often sold as “bridal wreath spireas” in catalogs.
Although spireas are typically not large plants, they do grow quickly.
Spireas are valued for their form and flowers. They are used as a specimen plant or as a hedge, screen, or border. Smaller cultivars can make nice accent plants for a border perennial garden. Most spireas are deciduous shrubs, and some have colorful fall foliage. Spirea flowers are often visited by butterflies. Spireas are generally deer resistant.
Fall is the best planting time, as it is for most shrubs. Spireas are also easy to dig and transplant to new sites, and late fall after leaf drop is the best time for moving these shrubs. These shrubs grow best, more dense, and produce more blooms in full sun. Spireas are tolerant of many soils except those that are extremely wet. The plant also responds well to applied mulch and summer watering.
After flowering has finished, prune the mostly spring-blooming spireas. Thin out old and weak canes to the ground annually. Prune the summer-blooming, bumalda spireas in winter or early spring. The bumaldas generally need less severe pruning than other species of spireas. After flowers on any spirea cultivar fade, remove them and a second flush of growth is stimulated, which will result in additional flowers.
Like other members of the rose family, spireas are susceptible to various pests and diseases, but most are not serious.
Diseases: Phytophthora or Pythium root rots could occur in poorly drained, wet soils, but these soils should be avoided for almost any type of shrub.
Phyllosticta and Cylindrocladium leaf spots have been reported on S. x bumalda cultivars, but are uncommon. Any shrub watered by over-head irrigation is more apt to contract a foliar fungal disease, so drip irrigation is always the best choice. Sprays with chlorothalonil (such as Daconil) will help control fungal leaf spot diseases. Rake or blow out fallen diseased leaves during the late winter and dispose of them to aid in disease control.
Insect Pests: Aphids are occasionally a problem in the spring. Spray in the early evening with an insecticidal soap solution for aphid control, and repeat sprays as needed.
Invasiveness: Japanese spirea (Spiraea japonica) is considered invasive in the Southeast US. Because of this potential, Japanese spirea and its cultivars are not recommended as suggested landscape plants*. Bumalda spireas (S. x bumalda) are crosses between S. japonica var. albiflora and S. japonica. These are also Japanese spireas and may be invasive. The most commonly produced cultivars, and there are many, are included last for purely educational purposes, so that if cultivar names only are listed in a catalog or in a nursery, SC residents will realize that these are Japanese spireas.
Reference: *The Southeast Exotic Pest Plant Council
Cultivars for SC Landscapes
- S. cantoniensis ‘Lanceolata’: This cultivar is a double-flowered Reeves spirea. Blooms are made as many-petaled, miniature roses. Plants grow to 4 to 6 feet tall and 6 feet wide. For USDA zones 5 to 9b.
- S. thunbergii Gold Thread™ (‘Ogon’): (by Garden Debut® Plant Collection). Gold Thread grows to 3 to 4 feet tall and wide. It has chartreuse, willow-like leaves and blooms in the spring with white flowers before the foliage appears For USDA zones 3 to 8.
- S. x vanhouttei ‘Renaissance’: This cultivar grows to 5 feet tall and 6 feet wide with graceful, arching branches. Bred for increased foliar disease resistance It has a massive display of pure white flowers, and its fall color is orange-red. For USDA zones 3 to 8.
- S. media Blue Kazoo® Double Play® Series (‘SMSMBK’ PPAF): (by Proven Winners). This cultivar grows to 2 to 3 feet tall and wide. New growth appears burgundy and changes at maturity to blue-green. Fall color is red. Blooms in spring with white flowers. For USDA zones 3 to 8b.
- S. media Snow Storm™ (‘Darsnorm’): (by Proven Winners). Plants grow 3 to 5 feet tall and wide. Foliage is blue-green during the summer, with orange and red colors in fall. Tiny white flowers make dome-shaped clusters that appear in late spring through early summer. For USDA zones 4 to 8.
- S. x cinerea First Snow® (‘Grefsheim’): Plants are a hybrid of (S. hypericifolia × S. cana), and grow 4 to 5 feet tall and wide with dense arching stems. This cultivar is an early bloomer – before the soft green foliage appears. The flowers are white and fragrant. For USDA zones 4 to 7.
- S. nipponica ‘Snowmound’: This white flowered cultivar grows 2 to 4 feet tall and wide in late spring with attractive arching stems. Foliage is a dark, blue-green. Prune after flowering. For USDA zones 3 to 8.
- S. betulifolia ‘Tor’: This birchleaf spirea grows as a dense, rounded mound to 2 to 3 feet tall and wide. It has tiny white flowers in clusters over the foliage in late spring. The dark green, oval leaves turn orange, red and purple in fall. Prune in late winter if needed. For USDA zones 4 to 8.
- S. betulifolia ‘Tor Gold’ Glow Girl® PPAF: (by Proven Winners). This birchleaf spirea grows to 3 to 4 feet tall and wide with a compact habit. It has white flowers in late spring, and lemon-lime foliage. For USDA zones 3 to 8.
Japanese Spirea Cultivars
- S. x bumalda ‘Anthony Waterer’: Grows to 2 to 3 feet tall by 3 to 4 feet wide and is a low maintenance plant. Flowers are carmine-red in flat-topped clusters, and flowers on new growth. Fall color of foliage is purple. For USDA zones 4 to 8.
- S. x bumalda ‘Dolchia’: New growth is purplish-red and leaves have frilly serrated margins. Plants grow to 2 to 3 feet tall and 2 to 4 feet wide. Flowers are bright pink in late spring. Fall foliage is a rich red. For USDA zones 5 to 9.
- S. x bumalda ‘Goldflame’: Blooms in the summer with bright pink flowers. Grows to 2 to 3 feet tall and wide. New foliage is orange-gold and matures in summer to light green. Fall foliage color is copper-orange. For USDA zones 4 to 8.
- S. x bumalda Golden Sunrise™ (‘Monhud’): This cultivar is a branch sport of ‘Goldflame’, and has bright yellow new growth that changes to a yellow green in summer. Fall color of foliage is coppery orange. Blooms during the summer with pink flowers. Plants grow 3 feet tall by 4 feet wide.
- S. x bumalda Limemound® (‘Monhub’): This cultivar is a branch sport of ‘Goldflame’. New growth is a bright lemon-yellow that matures to lime green. Grows to 3 feet tall and 4 feet wide. Hot pink flowers appear in early summer. Fall color is orange red with red stems. For USDA zones 3 to 8.
- S. x bumalda Little Bonnie™ (‘BL0601’): (Southern Living Plant Collection): Plants grow 2 to 3 feet tall and 3 feet wide. Flowers are lavender-pink during the summer. Foliage emerges bronze-red and matures to a bluish-green. For USDA zones 4 to 9.
- S. x bumalda Sundrop™ First Editions® Series (‘Bailcarol’): Plant grows to 12 to 15 inches tall by 2 to 3 feet wide. Pink flowers during the summer are accented by golden yellow foliage. For USDA zones 3 to 8.
- S. x bumalda ‘Fire Light’: Orange new growth matures to golden yellow. Flowers are produced in the summer and are pink. Has fiery red fall color. Plants grow to 2 to 3 feet tall and 4 to 5 feet wide. For USDA zones 4 to 7 (8).
- S. x Big Bang™ Double Play® Series (‘Tracy’ PP2158): Plants grow to 2 to 3 feet tall and wide. New foliage growth is a bright pumpkin orange and matures to a yellow-gold for summer and fall. Flowers are pink. For USDA zones 3 to 9b.
- S. x Solar Flare (‘Zelda’ PP21976): New leaves are orange-red and mature to a bright yellow with orange tips. It has large clusters of pink flowers in summer. For USDA zones 4 to 8.
- S. x bumalda Little Bonnie™ Dwarf Spirea (‘BL0601’): Plants grow to 2 to 3 feet tall and 3 feet wide. Has profuse lavender-pink blooms in spring and sporadically in summer.