Giant fleeceflower (Persicaria polymorpha) is a big, bold, hardy perennial that blooms in July and August. It reaches a height of 4 to 6 feet and is topped with large, feathery white plumes. The plant can take full sun or partial shade and is somewhat drought-tolerant once established. The leaves on the upright stems are lance-shaped. This species is not considered invasive, as are some other fleeceflowers. Although the flowers resemble goatsbeard, this species is in the buckwheat family, and it blooms after goatsbeard is finished.

Recent taxonomic treatments in the Flora of China—an international collaborative effort to publish the first English-language account of China's vascular plants—have changed the name to Aconogonon polymorphum, reflecting differences in the pith of the stem, flower, and seed structure.