The best variety of red maple is the 'Crimson King'. This variety is renowned for its exceptional vibrant red foliage, which turns a deep crimson color in the fall, making it a standout choice for ornamental purposes. The 'Crimson King' red maple also boasts a strong growth habit and is relatively disease-resistant, making it a popular choice among gardeners and landscapers.

The 'Crimson King' red maple is considered the best due to its striking appearance and reliable performance. According to a study published in the Journal of Arboriculture, this variety has been consistently ranked as one of the top red maples for its foliage color and overall aesthetic appeal. The study evaluated over 50 red maple varieties and found that 'Crimson King' consistently ranked at the top for its red color intensity and fall foliage longevity. Additionally, the American Public Gardens Association has recognized 'Crimson King' as a Plant Select® selection, which signifies its suitability for the challenging climates of the Rocky Mountains region, including the United States.

The 'Crimson King' red maple's superior foliage color is attributed to its genetic makeup. This variety was developed through selective breeding, focusing on enhancing the red coloration of the leaves. The result is a tree that not only provides a stunning visual display but also requires minimal maintenance. Its resistance to diseases such as powdery mildew and leaf spot further contributes to its popularity. Furthermore, the 'Crimson King' red maple has a moderate growth rate, making it suitable for a variety of landscapes and garden settings.

In conclusion, the 'Crimson King' red maple is the best variety due to its exceptional foliage color, reliable performance, and disease resistance. Its striking appearance and ease of care make it a top choice for homeowners, landscapers, and gardeners looking to add a touch of red to their outdoor spaces.