A Colourful Staple For Every Garden
Common Name: Japanese spirea, Japanese meadowsweet
Botanical Name: Spiraea japonica
Form: round to vase shaped
Plant Type: deciduous shrub
Mature Size: 4 - 6 ft x 5 - 7 ft
Origin: China, Japan
Hardiness Zone: 3 to 8
Foliage: up to 3” long, oval, serrated, fall and spring colours, green in summer
Flowers: flat topped clusters (corymbs) of tiny pink flowers June with repeat blooms
Fruit: small seeds held in capsules
Exposure: sun, light shade
Soil: soil tolerant, prefers moist loams
Uses: massing, accent, rock gardens, shrub border, hedge, foundation plantings, containers, small gardens, formal, informal, cottage
Attracts: butterflies, bees
Maintenance: low, easy care, durable
Tolerates: clay soil, air pollution, deer, erosion
Invasive Tendencies: Eastern USA
Propagation: potential to self seed, may sucker
Pruning: remove spent flowers, prune late winter, early spring
Problems: no serious issues
Japanese spireas are little shrubs known for their flat pink flower clusters. They are a common shrub and a favourite of many gardeners because they are a nice size, reliable bloomers, are easy care and love the sun. Japanese spireas are often used around the foundation of houses as they don’t get obnoxious.
Note that the species Japanese spireas, also referred to as Japanese meadowsweet, send out suckers, which maybe problematic if there isn't adequate space. They are considered an invasive species in Eastern US. Cultivated varieties and hybrids are not as prone to suckering.
Pollinators, especially butterflies and bees, love to rest on their flat flowers while they sip nectar and gather pollen. The initial flowering period starts in June and continues for about a month depending on the weather. Sporadic flowers occur during the summer, however, to encourage lots of new flowers, remove spent flowers asap.
Japanese spireas are dense shrubs with many stems. Each stem produces a flower on new growth so if there are many stems there are many flowers, but they will be small. To increase the size of the blossom clusters, thin spireas in late winter or early spring. Remove all crossing, weak and old stems.
Plant breeders have surpassed themselves when it comes to creating cultivars that are not only grown for their flowers, but for their foliage. Proven Winner’s Double Play Big Bang one of numerous stellar Japanese spirea cultivars. The Double Play moniker denotes that there is more to this cultivar than the species. The flower clusters are bigger, pinker, with orangey-red spring foliage that matures to a chartreuse. The bright pink flowers are accentuated by the contrasting yellow-green foliage. In autumn, the leaves changes colour once again to a brick red. It grows 2 to 3 feet (60-90 cm) tall and wide.
Anthony Waterer spirea (Spiraea X bumulda 'Anthony Waterer') has been around since the late 1800’s. It’s popularity is due to it’s compact and dense growth. It’s the perfect size for urban gardens as it grows from 2-3ft tall and 3-4ft wide. Six-inch flattened flower clusters (corymbs) bear deep carmine red flowers. New foliage is red with a purple tinge, which ages to a bluish-green in summer then turns a brick red in autumn.
Spiraea japonica ‘Goldflame’ formerly S. x bumalda 'Goldflame' bears rose-pink flowers on arching stems. Reblooms after deadheading. It grows 2 to 3ft tall and wide. Bronze-red leaves emerge in spring, mature to green then turn yellowish copper in autumn. It’s more sprawling with irregular growth compared to other cultivars and hybrids.
There are many spirea cultivars available so do your research, read the labels and include at least one of these reliable, low care pretty shrub in your garden.