Hemerocallis citrina, commonly known as the Citron Day-lily, is a species of herbaceous perennial plant belonging to the genus Hemerocallis. This species is distinguished by its fragrant, lemon-yellow flowers and is a valuable component of ornamental gardens, offering a unique aesthetic and olfactory experience. The Citron Day-lily typically grows to a height of approximately 60 to 90 centimeters, forming clumps of arching, strap-like leaves. These leaves are linear, typically 30 to 70 centimeters long and 1 to 2 centimeters wide, and are a vibrant green. The plant's most striking feature is its inflorescence, which bears multiple flowers. Each flower is trumpet-shaped, measuring about 10 to 12 centimeters in diameter, and possesses a distinct, pleasant citrus-like fragrance, a characteristic that gives the species its common name. The petals and sepals, known as tepals, are a uniform pale yellow to lemon-yellow color. Flowering typically occurs in midsummer. Following successful pollination, the plant may produce a capsule containing seeds, though this is less commonly observed or emphasized in horticultural contexts compared to its floral display. Hemerocallis citrina is native to China, specifically found in provinces such as Anhui, Jiangsu, and Zhejiang. It thrives in its natural habitat in woodland clearings, along stream banks, and on grassy slopes, often in moist, well-drained soils. In cultivation, it is adaptable to a wide range of soil types, provided they are not waterlogged. The Citron Day-lily prefers full sun to partial shade, with at least six hours of direct sunlight daily for optimal flowering. It is a hardy plant, generally tolerant of a variety of climatic conditions once established. Regular watering is beneficial, especially during dry periods, and occasional fertilization can promote vigorous growth and abundant blooms. The primary significance of Hemerocallis citrina lies in its ornamental value. Its fragrant, bright yellow flowers make it a desirable addition to perennial borders, cottage gardens, and landscape designs where its scent can be appreciated. While other Hemerocallis species have been extensively hybridized for a vast array of colors and forms, Hemerocallis citrina retains its appeal for its specific fragrance and classic coloration. There is limited scientifically documented evidence regarding significant medicinal, culinary, or economic uses for this particular species, with its cultivation predominantly focused on horticultural and aesthetic purposes. An interesting characteristic of Hemerocallis citrina is the nocturnal opening of its flowers, a trait shared by many day-lily species, though their lifespan is typically limited to a single day. The pronounced fragrance is a key adaptation, likely serving to attract pollinators. The plant's ability to form dense clumps also helps in soil stabilization and can contribute to the suppression of weeds in garden settings. Its resilience and relatively low maintenance requirements further enhance its popularity among gardeners seeking both visual beauty and aromatic appeal.