Schiedea laui is an upright to strongly ascending (sloping or leading upward) subshrub that is 5 to 15 dm (1.6 to 4.9 ft) tall. The stems are many-branched and glabrous (free from hair) except for the bracts (a modified leaf or scale) and sepals (each of the parts of the calyx of a flower, enclosing the petal). The internodes (a part of a plant stem between two of the nodes from which leaves emerge) are lightly purple-tinged. The leaves are opposite, narrowly ovate (oval shape, like an egg) or lanceolate (of a narrow oval shape tapering to a point at each end) to narrowly or broadly elliptic, dull green and sometimes purple-tinged. The petioles (the stalk that joins a leaf to a stem) are 0.5 to 1.1 cm (0.2 to 0.4 in) long. The inflorescences are terminal containing 10 to 18 flowers. The flowers are hermaphroditic (also known as "perfect", which means that each flower contains both male and female structures) and cleistogamous (flowers that do not open and are self-pollinated). The sepals are narrowly lanceolate, 4.0 to 4.5 mm (0.16 to 0.18 in) long, and green to sometimes purple-tinged or nearly purple throughout. The nectary base is obsolete. The capsules are narrowly ovoid (egg-shaped, with the axis widest below the middle) and approximately 4.0 to 4.5 mm (0.16 to 0.18 in) long. The seeds are orbicular-reniform (having the shape of a flat ring or disk-kidney-shaped) and approximately 1 mm (0.04 in) long. Schiedea laui is most similar in morphology to S. nuttallii differing by the presence of cleistogamous flowers and occurring at higher elevations in wet forest habitats, rather than mesic forests. Schiedea laui also does not share any unique synapomorphies (a characteristic present in an ancestral species and shared exclusively by its evolutionary descendants) with S. nuttallii.