Full sun is best for miscanthus; when planted in part sun, the grass tends to flop. Full sun also gives miscanthus the most intense fall color possible, which, depending on the variety, can be a stunning purple, red, orange, or gold. Fast-growing Miscanthus species usually reach their maximum height and spread within their first few years. Depending on the species and cultivar, their ultimate size varies from around two to 12 feet tall.