Philadelphus x ‘Snowbelle’ – A dwarf form of Mockorange which bears very fragrant double white blooms in late spring. It forms a compact, mounded deciduous shrub which is much more suited to urban gardens than the taller old-fashioned cultivars. ‘Snowbelle’ prefers part to full sun, features dark green foliage and can be grown in large containers. Grows 4′ tall and is hardy to zone 4.
Hydrangea arborescens ‘Annabelle’ – A hardy deciduous hydrangea with huge (up to 12″ across) flattened balls of pure white blooms from July to September – these emerge lime green and also are good for dried arrangements. This species flowers on new wood and is best pruned down to 18-24″ in early spring. Tolerates full sun here in coastal BC. Height 3-5′ tall. Zone 4.
Fothergilla ‘Mount Airy’ – This cultivar of Witch Alder blooms April to May (just after the leaves begin to emerge) with abundant honey-scented white bottlebrush blooms. The Witch hazel-like leaves also have excellent autumn tones of orange, yellow and red. ‘Mount Airy’ is thought to be a hybrid form, but the lineage has yet to be determined. Grows 4-5′ tall and is hardy to zone 5.
Rosa ‘Iceberg’ (Kordes 1958) ( ‘Robin Hood’ x ‘Virgo’) (syn. ‘Korbin’) – One of the most common floribunda roses even today, it features clusters of lightly fragrant double white blooms that emerge from pink-tinted buds. This Award of Garden Merit winner flowers from July to October and has very dark green foliage. A climbing form is also available. Height 3-4′. Zone 6.
Choisya x ‘Aztec Pearl’ (syn. Choisya x dewitteana) – This hybrid of C. ternata and C. arizonica has two bloom flushes, one in May-June and the other around September-October. The fragrant white flowers emerge from pink buds and are nicely contrasted by glossy foliage with thin strap-like lobes. This broadleaf evergreen grows 6-7′ tall and wide. Hardy to zone 8.