Hosta is a genus of about 23–45 species of lily-like plants. Hostas are herbaceous perennial plants, growing from rhizomes or stolons, with broad lanceolate or ovate leaves varying widely in size by species from 1–15 in (3–40 cm) long and 0.75–12 in (2–30 cm) broad.
Variation among the numerous cultivars is even greater, with clumps ranging from less than 4 in (10 cm) across to more than 2.5 ft (76 cm) across. Some species have a glaucous white coating covering the underside of the leaves. Natural mutations of native species are known with yellow-green (gold) colored leaves or with leaf variegation (either white/cream or yellowish edges or centers).
The flowers are produced on erect scapes up to 31 in (80 cm) tall that end in terminal racemes. The individual flowers are usually pendulous, 0.75–2 in (2–5 cm) long, with six tepals, white, lavender, or violet in color and usually scentless. The only strongly fragrant species is Hosta plantaginea; it is also unusual in that the flowers open in the evening and close by morning. This species blooms in late summer and is sometimes known as "August Lily."