Astilbe chinensis is a clump-forming herbaceous perennial that typically reaches about 18 to 36 inches in height at maturity, though some vigorous cultivars can stretch closer to 40 inches tall when in bloom, with a spread ranging from roughly 18 to 24 inches wide as the plant gradually expands by rhizomes. Its upright flower plumes rise above the foliage on sturdy stems that are usually 20 to 30 inches long, with the feathery inflorescences themselves measuring approximately 6 to 12 inches in length and 2 to 4 inches across, forming dense, tapering spikes. The compound leaves, which are coarsely toothed and often slightly glossy, typically measure 6 to 12 inches long overall, with individual leaflets about 2 to 4 inches in length and 1 to 2 inches wide, arranged in a layered, fern-like pattern that gives the plant a full, textured appearance. Basal clumps can thicken over time to about 1 to 2 feet in diameter, while the root system spreads slowly underground with short, thick rhizomes extending a few inches outward each growing season. Flower stalks are generally about 1/4 to 1/2 inch thick, supporting the airy plumes that maintain their structure even after blooming, often drying in place and adding seasonal interest.