Perennial hibiscus, also known as hardy hibiscus or perennial rose mallow, refers to a group of Hibiscus species and cultivars that are perennial in nature and can withstand colder temperatures. Here are some key points about perennial hibiscus:

1. Appearance: Perennial hibiscus plants typically feature large, showy flowers with prominent stamens and pistils. The flowers come in a variety of colors, including shades of pink, red, white, and purple. The foliage is usually medium to dark green and may have a lobed or palmate shape.

2. Size: Perennial hibiscus plants vary in size depending on the species or cultivar. Some may grow as small shrubs reaching 4 to 5 feet (0.9 to 1.2 meters) in height, while others may be larger, reaching heights of 6 feet (1.8 meters) or more.

3. Flowering: Perennial hibiscus plants typically bloom in late summer to early fall, producing large, showy flowers that can measure up to 12 inches (30 cm) in diameter. The flowers are short-lived, usually lasting only a day or two, but the plants produce numerous buds, resulting in a prolonged flowering period.

4. Sun and Soil Requirements: Perennial hibiscus plants prefer full sun to partial shade. They thrive in well-draining soil that is rich in organic matter. While they can tolerate a wide range of soil types, they perform best in fertile, moist soil.

5. Watering: Perennial hibiscus plants have moderate water needs and benefit from regular watering, especially during hot, dry periods. However, they are somewhat drought-tolerant once established and can withstand short periods of dryness.

6. Maintenance: Perennial hibiscus plants are relatively low-maintenance. Deadheading spent flowers can help promote continued blooming and prevent self-seeding. Pruning may be necessary in early spring to remove dead or damaged wood and encourage new growth.

7. Landscape Use: Perennial hibiscus plants are commonly used in borders, mass plantings, and mixed perennial gardens, where their large, colorful flowers add visual impact. They also work well as specimen plants or focal points in the landscape.

Overall, perennial hibiscus plants are prized for their large, showy flowers and long blooming period, which adds color and interest to garden landscapes in late summer and early fall. With their adaptability to various growing conditions and relatively low maintenance requirements, they are popular choices for gardeners seeking vibrant and reliable perennial plants.