Shrub 1 - 3 m tall Leaves: stalked, 5 - 10 cm long, egg-shaped to elliptic with a pointed tip and rounded to broadly wedge-shaped base, few-toothed, nearly hairless above, usually densely hairy beneath. Flowers: borne five to seven in an inflorescence (raceme), very lightly fragrant, 2.5 - 4 cm across, with four hairy sepals, four large white petals, and many stamens. Fruit: a hardened capsule, inversely egg-shaped, four-chambered, many-seeded. Twigs: gray, not exfoliating.
Similar species: Philadelphus floridus and Philadelphus inodorus both have non-fragrant flowers borne solitary or in clusters of three. Philadelphus coronarius has brown twigs that exfoliate with age and leaves with hairs only in the vein axils of the lower surface.
Habitat and ecology: Introduced from farther south. In the Chicago Region, escapes were found in waste ground, disturbed woodland, along a ravine edge, and along railroad tracks.
Occurence in the Chicago region: non-native
Etymology: Philadelphus is named after a Greek king, but also means "brotherly love." Pubescens means hairy.
Stiffly branched shrub 1-3 m; bark of young twigs gray, not exfoliating; lvs ovate-elliptic, 5-8 cm, acuminate, glabrous above, the lower surface (as also the pedicels, hypanthium, and outer side of the sep) usually soft-hairy, but varying to glabrous; fls in racemes of 5-7, 2.5 cm wide, scarcely or only slightly fragrant; 2n=26. On limestone river-bluffs; Ky. and Tenn. to Ala., Mo., s. Ill., Okla., and e. Tex. May, June. (P. intectus, the glabrous extreme)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.