Wooly lousewort is a robust forb usually found in tundra, with a thick cylinder of pink flowers and a stem covered in a mat of wooly white hairs. The taproot is stout, branched, and lemon-yellow when fresh. Each plant has a single unbranched stem, growing 5-25 cm tall. The leaves are green-purple and pinnatifid. There are many stem leaves, the lower leaves with long petioles, the upper with short. The petioles are broad. Flowers are pink or rarely white and bilaterally symmetric. The upper petal is hooded, the tip blunt and untoothed. The lower petal has three rounded lobes. The four stamens have white filaments and black-yellow anthers, contained within the upper petal. Fruits are a capsule. Wooly lousewort can be distinguished from the other hairy, pink-flowered lousewort, Pedicularis langsdorffii, by the lack of stem leaves and toothless upper petal, and the presence of dense wooly hairs covering the stalk.
Pedicularis lanata is an early-flowering perennial. When young, plants can look like conical cotton-balls with a few leaves sticking out. The inflorescences soon elongate and the hairiness of the plant is slightly overshadowed by the many brightly-colored flowers. The stems elongate even more in fruit.
Pedicularis lanata is monoecious with bisexual flowers. Wooly lousewort is bumblebee-pollinated and nectar-producing. It is also protogynous—the female part of the flower is able to receive pollen before pollen is released from the same flower (Williams and Batzli 1982). This mechanism serves to reduce self-pollination. P. lanata can be self-fertilized, but this reduces seed set compared to out-crossed plants. Like other Pedicularis species, woolly lousewort is hemi-parasitic: it photosynthesizes but also steals water and nutrients from the roots of nearby plants.
Wooly lousewort is an amphi-Beringian species with an arctic-alpine distribution that is primarily northern North American, reaching only Chukotka in Eurasia. This species occurs in Alaska, northern Canada and Greenland in North America, and throughout tundra regions in Alaska, except that it is rare in the southeastern mountains, and it does not reach the Aleutians past Unalaska Island. In Denali, P. lanata is common in tundra north of the Alaska Range crest, and also in the upper Chulitna River drainage.