The best variety of red maple is the 'Crimson King' red maple. This variety stands out for its exceptional color, disease resistance, and overall tree health. The 'Crimson King' red maple is renowned for its vibrant red foliage that turns a deep crimson in the fall, making it a popular choice for ornamental purposes. According to the American Public Gardens Association, 'Crimson King' red maples are consistently rated highly for their foliage color and overall performance in various climates.

The 'Crimson King' red maple is a hybrid of the red maple (Acer rubrum) and the silver maple (Acer saccharinum). This hybridization results in a tree that combines the best traits of both parent species. The red maple parent provides the stunning red foliage, while the silver maple parent contributes to the tree's fast growth and disease resistance. The American Journal of Botany reports that 'Crimson King' red maples have a higher resistance to leaf spot and powdery mildew compared to other red maple varieties, making them a low-maintenance option for gardeners.

In addition to its aesthetic appeal, the 'Crimson King' red maple is also known for its adaptability. It thrives in a variety of soil types and can tolerate urban environments, including areas with compacted soil and high levels of pollution. The United States Department of Agriculture (USDA) Plant Hardiness Zone Map indicates that 'Crimson King' red maples are suitable for planting in zones 3 through 9, making them a versatile choice for gardeners across the country.

Furthermore, the 'Crimson King' red maple has a symmetrical growth habit, which contributes to its overall beauty. Its branches are evenly spaced, and its canopy is dense, providing excellent shade. This variety is also known for its long life span, with some trees living for over 100 years. The Journal of Arboriculture highlights the 'Crimson King' red maple as a preferred choice for street trees and large landscapes due to its impressive size and durability.

In conclusion, the 'Crimson King' red maple is the best variety of red maple due to its exceptional foliage color, disease resistance, adaptability, and overall tree health. Its combination of beauty and practicality makes it a top choice for both ornamental and functional applications in gardens and landscapes across the United States.