Schiedea perlmanii is a vine species that typically exhibits stems swollen at the nodes, terete, and either 4-angled or -ridged, growing between 60 to 120 cm long in natural conditions and potentially over 150 cm in cultivation. These stems are sprawling in younger plants and recline as they lengthen. They display a deep purple or purplish-green coloration and are glabrous except for the bracts, sepals, and sometimes the pedicel. A fibrous root system supports this species. The leaves are simple and opposite, with narrowly ovate blades or lanceolate to elliptic-lanceolate, measuring 6.5 to 11.5 cm in length and 2 to 2.8 cm in width. The leaf apex ranges from acute to acuminate, and the bases are often connate around the stem. The surfaces of the leaves are weakly glossy, green or yellowish-green, and occasionally purple-tinged, particularly on the lower surface. When dry, the blades are weakly coriaceous, rubbery, and chartaceous, with only the midvein visible. The margins are entire, slightly thickened, and become revolute towards the base. The midvein is somewhat eccentric and usually reddish-purple. The petioles are 0.8 to 0.9 cm long, purple, and weakly grooved. Stipules are absent. The inflorescence is terminal, with 40 to 60 flowers on a structure measuring 20 to 35 cm long and nearly as wide. It is diffuse, laterally directed, or pendent, with tertiary and higher-level internodes or pedicels weakly spreading. The bracts are subulate (tapering to a point), with the lowermost narrowly elliptic and falcate, green and purple-tinged or purple. The pedicels are 13 to 15 mm long at anthesis, weakly flattened. The flowers are bisexual (perfect) and usually pendent. The sepals are 2.2 to 3 mm long, elongating to 4 mm in fruit, ovate, green, and sometimes purple-tinged. The corolla (petals) is absent. There are 10 stamens with dimorphic filaments and pale yellow anthers. The superior ovary is 1-celled, with free-central ovule placentation and 3 white styles. The fruit is an ovoid capsule, 2.5 to 2.7 mm long, with seeds approximately 1.2 mm long, orbicular-reniform, compressed. The perisperm (nutritive tissue surrounding the embryo) is starchy, with no true endosperm. It is found in mesic shrublands between 410-570 meters.