Philadelphus

Philadelphus, or mock-orange, is a genus of deciduous shrubs in the family Hydrangeaceae. The genus includes about 60 species native to temperate regions of the Northern Hemisphere, especially North America and East Asia. They are widely grown as ornamental shrubs for their highly scented flowers.

Most species are 1–3 meters tall, sometimes taller. The leaves are opposite, simple, ovate to lanceolate with serrated margins. In late spring to early summer, plants produce clusters of single or double flowers, usually white or pale cream, with four petals and a strong citrus-like fragrance. The fruit is a dry capsule containing seeds.

Cultivation: Philadelphus tolerates full sun to partial shade and prefers fertile, well-drained soil. They are hardy to temperate climates, generally USDA zones 4–8. Most species bloom on last year's wood, so pruning is best done right after flowering to maintain shape and encourage new shoots. Propagation is commonly achieved by semi-ripe cuttings or layering.

Notable species and hybrids: Philadelphus coronarius (sweet mock-orange) is one of the best-known cultivars for fragrance. Philadelphus lewisii (Lewis's mock-orange) is native to western North America. Numerous hybrids and cultivars, collectively known as Philadelphus x lemoinei, are widely grown for garden use.

Taxonomy and etymology: The genus belongs to Hydrangeaceae in the order Cornales. The name Philadelphus derives from Greek words meaning 'brotherly love,' and the common name reflects the plant's strong, citrusy perfume.