Spirea cantoniensis

Spiraea cantoniensis, the Reeve's spiraea, bridalwreath spirea, double white may, Cape may or may bush, is a species of plant native to China, belonging to the rose family Rosaceae. An ornamental plant featured in gardens, it is a shrub growing up to 1.5 metres (4.9 ft) tall with frothy, pompom-like clusters of snow-white flowers borne along arching branches that bloom in May in its native country, hence its common name.
It is a deciduous or semi-evergreen shrub that reaches a size of 1–2 m height, with many thin branches, arched, flexible and glabrous. The leaves are alternate, simple, small petiolate, with 2–6 cm long green lanceolate, elliptical-rhomboidal or slightly obovate lamina, with 3 nerves parallel from its base, irregularly crenate-dentate in its distal half. The leaves may turn a yellowish red colour in autumn. Blooming in spring and snow white in colour, its flowers are hermaphroditic, actinomorphic, of ± 1 cm diameter, arranged in axillary corimbos, each with 5 free sepals, 5 white petals, numerous stamens shorter than the petals. The fruit is a poly-follicle, with 3-5 plurisemined carpidia (follicles).
Bridal-wreath Spiraea is a hardy plant that is drought and heat tolerant, slightly salt tolerant, and seldom damaged by deer. The plant is easily transplanted, grows rapidly, and will often require pruning, which should be done after the plant has completed flowering. It grows in a range of soil types with the exception of wet soil and produces new stems from the base of the plant. It is best grown in cooler climates with protection from the hot afternoon sun as that can cause leaf burn.
The flowers attract butterflies. 
Insects, Diseases, and Other Plant Problems
This plant is relatively pest and disease-free.