Plants usually slender, sometimes robust, but then not very compact . Stems glabrous or hirsute in lines. Leaf blades ovate-lanceolate or lanceolate to oblanceolate, 7-9 times as long as wide, bases ± clasping. 2n = 48. Flowering Aug-Sep. Sand dunes, sandy or stony upper seashores, saltmarshes, sandy, gravelly or rocky stream shores, edges of moist thickets, edges of sea cliffs, ultramafic barrens, seaside meadows, open seaside mountain heath and meadows; 0-800 m; St. Pierre and Miquelon; N.B., Nfld. and Labr., N.S., P.E.I., Que.; Conn., Maine, Mass., N.H., N.Y., Pa., R.I., Vt., W.Va.; introduced in Mexico, Europe, Australia. Several cultivars of var. novibelgii are sold in the horticultural trade. The following forms are not recognized here, as they represent mere color variants: forma novibelgii, forma albiflorus (Victorin) J. Rousseau, and forma roseus E. L. Rand & Redfield.

Symphyotrichum ×subgeminatum (Fernald) G. L. Nesom (as species) (syn.: Aster subgeminatus Fernald) is the hybrid of var. novibelgii with S. ciliolatum; it has been observed in western Newfoundland and the Gaspé (Quebec). Variety novibelgii also hybridizes with S. anticostense (L. Brouillet and J. Labrecque 1987).