Hibiscus syriacus tree, or "shrub althea," is much beloved and widely planted. The virtues of Hibiscus syriacus include:

• A long summertime blooming period
• A large, colorful flower
• A tolerance for cold weather

Want to learn more? The Rose of Sharon Association provides photos of some of the varieties of Hibiscus syriacus. Interestingly, this organization is currently raising funds to finance a very ambitious project, namely, to distribute a total of 1,000,000 Hibiscus syriacus specimens "all over North America in the next 30 years. Also, to encourage a similar campaign of planting 10,000,000 trees in Korea."