The cultivar 'Anthony Waterer' of this species is a compact deciduous shrub (ht around 1 m) with narrow, toothed leaves. Its new foliage in spring is bright lime-green. All through summer it bears clustered heads of tiny rosy pink flowers. The species comes from China and Japan and is suitable for a range of climates from the very cold to the warmer zones, including Sydney. It enjoys a sunny position with reasonable moisture, but is quite adaptable to less than ideal conditions once established. It is also said to tolerate light shade.
If the flowers are clipped off once they are finished, a whole new flush of blooms will appear, and this can be done several times through summer. It should be pruned completely after flowering is over; some old stems can be removed at the base each year. Propagation is by cuttings taken in early summer.
There is another cultivar called 'Goldflame', which has lovely golden foliage, but I don't particularly like the combination of those leaves with the pink blooms. I also have a white-flowered, green-leaved version, which is pretty. Spiraea belong to the Rosaceae family of plants.