Common Name: Japanese Spiraea

General Information

Spiraea japonica is an erect, deciduous shrub forming a dense mound of growth; it can grow up to 150cm tall with a slightly larger spread[, ].
The plant is often grown as an ornamental, where it can be used as a low hedge and a ground cover.

Known Hazards

None known

Botanical References

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Range

E. Asia - China, Japan, Korea

Habitat

Mountains all over Japan[]. Forests, forested slopes, forest clearings, thickets, grassy slopes, mountain valleys, gullies, river banks, alpine steppes, rocky and stony places; also commonly cultivated; at elevations from 700 - 4,000 metres[].

Properties

Other Uses Rating
Habit	Deciduous Shrub
Height	1.50 m
Pollinators	Insects
Cultivation Status	Ornamental, Wild

Cultivation Details

Spiraea japonica is hardy to about -20°c[].
Tolerates most soils[], but prefers a good loamy soil, abundant moisture and full sunlight[, ]. Succeeds in part shade[].
Species in this genus generally hybridize freely with other members of this genus, and so seed cannot be relied upon to come true unless the plant has been grown in isolation from other species that are flowering at the same time[].
A very ornamental plant, there are many named varieties[].
The flowers are attractive to butterflies[].
The plant flowers at the ends of the current season’s shoots - to promote freer flowering it should be pruned in spring by cutting clean out sufficient of the older wood to prevent crowding, and then shortening back those selected to remain[].

Edible Uses

None known

Medicinal

None known

Agroforestry Uses:

Plants can be grown as a low hedge, the cultivar 'Albiflora' has been especially mentioned[]. 'Bumalda' has also been recommended[].
Plants, especially some of the low-growing cultivars, can be grown as a ground cover when planted about 1.2 metres apart each way[].

Other Uses

None known

Propagation

Seed - we have no information for this species but suggest sowing the seed as soon as it is ripe in a cold frame if possible. It is likely to require stratification before it germinates, so stored seed should be sown in a cold frame as early in the year as you receive it. Prick out the seedlings into individual pots when they are large enough to handle, and grow them on in a cold frame for their first winter. Plant them out in late spring or early summer of the following year.
Cuttings of half-ripe wood, mid summer in a light sandy soil a frame.
Cuttings of mature wood of the current seasons growth, 15cm long, autumn in an outdoor frame[].