Philadelphus is a genus of shrubs in family Hydrangeaceae, comprising 60 species. It is native to North America, Central America, Asia and southeast Europe. It is commonly known as Mock-orange, in reference to the flowers which are somewhat similar to that of the oranges and lemons, and smell of orange flowers and jasmine.
Philadelphus is a popular shrub in parks and gardens, grown for its lovely, scented late spring to early-summer flowers, but for the rest of the years, it is rather uninteresting, so it is best to plant the shrub at the back of a mixed border. When pruning is necessary, do it immediately after flowering because the next season's flowers will be borne on shoots produced in the current year.
Most of Philadelphus species are deciduous but a few species are evergreen. The leaves are opposite, simple, with serrated margins. The white flowers have four petals and sepals, and are sweetly scented. The fruit is a small capsule, containing numerous small seeds.
Philadelphus coronarius (Sweet Mock-orange, English Dogwood) is a species of deciduous shrub, native to Southern Europe. It is a popular ornamental plant in the temperate regions with a large numbers of cultivars. It is valued for its profusely sweetly scented white blossom in early summer. This species is also the parent of two most widely grown cultivars, P. 'Aureus' 2.4 x 1.5 m, has yellow-green leaves, and P. 'Variegatus' has leaves that are edged in cream.
P. 'Manteau d'Hermine' , 60 x 75 cm, produces double, very fragrant cream white flowers in early to mid-summer. P. 'Innocence', 1.5 x 1.2 m, has attractive leaves with splashes of cream color and bears lovely pure white, single flowers in midsummer.
Philadelphus species are food plants for larvae of some Lepidoptera species including The Engrailed (Ectropis crepuscularia).
Philadelphus grows well in sun or partial shade, in fertile and well drained soil. Propagation is by softwood cuttins in summer ; or hardwood cuttings in autumn. Aphids and mildew are the pest and disease that affect the growth of Philadelphus.