Common Name:

General Information

Spiraea thunbergii is a deciduous shrub with spreading, arching, slender branches; it can grow up to 150cm tall, and is often wider than it is tall[, , ].
The plant is often grown as an ornamental in gardens, where it can be used as a hedge[].
Widely grown as an ornamental in gardens, it has escaped from cultivation and become extensively naturalized in Japan[].

Known Hazards

None known

Botanical References

, ,

Range

E. Asia - eastern China, Japan.

Habitat

Rocky hillsides[].

Properties

Weed Potential	Yes
Other Uses Rating
Habit	Deciduous Shrub
Height	1.50 m
Pollinators	Insects
Cultivation Status	Wild

Cultivation Details

Spiraea thunbergii is tolerant of temperatures down to about -20°c[].
Prefers a position in full sun, but tolerates light shade[]. Tolerates most soils[], but prefers a good, well-drained, loamy soil and abundant moisture[, ]. Plants are tolerant of short periods of drought[].
Succeeds in most soils, but requires a warm sheltered position if the wood is to ripen sufficiently to induce free flowering[].
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[].
Plants flower on the previous summers growth and should be pruned immediately after flowering in order to promote new growth[].
The flowers are very attractive to butterflies[].
The leaves are slow to fall in autumn and sometimes remain on the bush throughout the winter[].

Edible Uses

None known

Medicinal

None known

Agroforestry Uses:

Plants can be grown as a medium sized hedge[].

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[].