Shrub 1 - 3 m tall Leaves: short-stalked, 4 - 8 cm long, egg-shaped to oblong with a pointed tip and rounded to wedge-shaped base, few-toothed or non-toothed, shiny and hairless above, sparsely hairy along veins and in vein axils beneath. Flowers: borne solitary or in clusters of three (cymule), non-fragrant, 3.5 - 5.5 cm across, cup-shaped, with four hairless sepals, four large white petals, and many stamens. Fruit: a hardened capsule, inversely egg-shaped, four-chambered, containing many long-tailed seeds. Twigs: brown, exfoliating in second year.
Similar species: Philadelphus coronarius and Philadelphus pubescens both have fragrant flowers in clusters of five or more. Philadelphus floridus has hairy sepals and densely hairy lower leaf surfaces.
Flowering: May to June
Habitat and ecology: Introduced from the southeastern United States. In the Chicago Region, an escape was found in dry, disturbed woods along a right-of-way. In its native range, this species usually grows in the mountains along streambanks and moist hillsides or cliffs.
Occurence in the Chicago region: non-native
Etymology: Philadelphus is named after a Greek king, but also means "brotherly love." Inodorus means unscented.
Arching shrub 1-3 m; bark of young twigs brown, exfoliating the second year; lvs ovate to oblong, 4-8 cm, toothed or entire, acuminate, rounded to acute at base, glabrous, or very sparsely hairy beneath; fls in cymules of 3 or solitary, 3.5-5.5 cm wide; hypanthium, pedicels, and outer side of sep glabrous; styles separate above; seeds long-tailed; 2n=26. Streambanks and moist hillsides or cliffs, chiefly in the mts.; e. Pa., Va. and Tenn., Ga. and Ala., sometimes escaped from cult. northward. May, June. (P. grandiflorus)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.