Large deciduous shrubs valued for their sweetly-scented, late-spring flowers, mock oranges (Philadelphus spp.) were widely planted several generations ago when shrubs were usually available only as bare-root plants in early spring, since these tough shrubs ship and transplant easily as dormant, bare-root plants. Mock oranges are big shrubs best suited to large yards, but plant them in a spot where you can appreciate their wonderful fragrance.
Single-Flowered Sweet Mock Oranges
Most mock oranges offered for sale today are cultivars of the European sweet mock orange (P. coronarius). This large, upright shrub grows 10 to 12 feet high and wide and is hardy in U.S. Department of Agriculture plant zones 4 through 8. It's covered in fragrant, single white flowers for two weeks in late spring. The scent is reminiscent of orange blossoms, hence the name. Commonly available varieties include sweetly-scented, free-blooming Innocence and Mont Blanc, a particulary hardy cultivar. Belle Etoile has 2- to 3-inch flowers with a maroon blotch in the centre and a more graceful habit than most mock oranges. Two varieties with interesting foliage include Aureus, with yellowish-green leaves, and Variegatus, with white margins on the dark green leaves.
Double-Flowered Mock Oranges
The double-flowered varieties of mock orange are particularly eye-catching. Glacier is a 5- to 6-foot shrub covered in small but very full, doubled flowers. Polar Star is a large shrub with big, semi-doubled flowers in late spring. This variety is not as cold-hardy as most mock oranges, handling winters only through zone 5, but makes up for it by re-blooming in the fall.
Dwarf Mock Oranges
Breeders have introduced compact mock oranges suitable for today's smaller yards. Nana, also marketed as Pumilus, stays 4 feet tall and wide but flowers less prolifically than its bigger cousins. The oddly-named Buckley's Quill grows 6 feet tall and 4 feet wide. Long, thin, pointed petals on the fragrant flowers give the shrub its name. Snow Velvet has very large, 3-inch flowers that repeat in the fall; the shrub grows 5 feet tall and wide.
Native Mock Oranges
Gardeners interested in native shrubs should seek out the hairy or streambank mock orange (P. hirsutus), native to the southeastern U.S. It's identified by the white hairs on the underside of leaves and on new stems. The scentless mock orange (P. inodorus) is native to fertile woodlands throughout the eastern United States. Lewis' mock orange (P. lewisii) is named for the explorer Meriweather Lewis, who collected samples of the shrub in the Pacific Northwest during the Lewis and Clark Expedition.
Growing Mock Oranges
Whether native or introduced, all mock oranges require the same minimal care. Site them in full sun for best flowering, although they perform adequately in light shade. Mock oranges flower on old wood so all pruning must be done right after flowering is finished. Tolerant of a wide range of soil types, they prefer moist, well-drained soil. The smaller varieties are suitable for urban gardens. Prune out one-quarter to one-third of the oldest canes each summer to keep the plant vigorous.