Yellow, five petaled flowers approximately 20mm across occur between late Spring and early to mid Summer. The flowers appear in in broad cymes at the ends of the upper branches. The sepals are pointed, with glandular dots in the tissue. There are many stamens, which are united at the base into three bundles.
Leaves exhibit obvious translucent dots when held up to the light, giving them a ‘perforated’ appearance, hence the plant's Latin name. The yellow-green leaves are sessile (having no stem), narrow, oblong leaves which are 12mm long or slightly larger.
Erect, branched in the upper section, and can grow to 1m high.
Oenothera biennis which has four petals rather than five.
The bright yellow flowers grow in clusters, have four parts, and have ribbon-shaped petals about one inch long. H. virginiana blooms in about mid fall and continues until late fall.
Alternate, simple, obovate or oval, four to six inches long, unequal at base, wavy-toothed, acute or rounded at apex. Feather-veined; midrib stout with six to seven pairs of primary veins. They come out of the bud involute, covered with stellate rusty down; when full grown, are dark green above, paler beneath; midrib and veins more or less hairy. In autumn they turn yellow with rusty spots. Petioles stout, half an inch to an inch long. Stipules lanceolate, acute, infolding the buds.
The fruit is a hard woody capsule about ½ an inch long, which explodes and launches two shiny black seeds up to 30 feet when it is mature.