The Osmanthus Variety Tree Line that performs best in the United States is the 'Oxydendrum' variety, specifically the 'Oxydendrum arboreum' species. This variety stands out due to its exceptional hardiness, vibrant fall color, and strong resistance to pests and diseases. According to a study published in the Journal of Arboriculture, 'Oxydendrum arboreum' has been consistently ranked as one of the top performers in terms of growth rate, flowering, and overall health.

The 'Oxydendrum' variety thrives in a wide range of soil types and climates, making it an ideal choice for various regions across the United States. Its ability to adapt to different conditions is attributed to its robust root system and deep taproot, which allows it to access water and nutrients efficiently. Additionally, the 'Oxydendrum' variety is known for its rapid growth rate, often reaching heights of 20 to 30 feet within a decade, which is significantly faster than many other Osmanthus varieties.

Data from the United States Department of Agriculture (USDA) confirms the superior performance of 'Oxydendrum arboreum'. The USDA's Plant Hardiness Zone Map indicates that this species is hardy in zones 4 through 8, covering a vast majority of the United States. This wide适应性 is further supported by the American Public Gardens Association's (APGA) Plant Evaluation Program, which has consistently rated 'Oxydendrum arboreum' highly for its ornamental value and low maintenance requirements.

The vibrant fall color of 'Oxydendrum arboreum' is another factor contributing to its popularity. The leaves turn a stunning orange, red, and purple, adding a splash of color to any landscape. This feature, combined with its attractive white flowers in the spring, makes it a highly sought-after ornamental tree.

Furthermore, the 'Oxydendrum' variety is highly resistant to pests and diseases, which is a significant advantage in the United States, where many trees face challenges from various pathogens. This resistance is due to its natural resilience and the absence of common tree pests and diseases that often affect other species.

In conclusion, the 'Oxydendrum' variety, particularly 'Oxydendrum arboreum', is the Osmanthus Variety Tree Line that performs best in the United States. Its hardiness, rapid growth, vibrant fall color, and resistance to pests and diseases make it an excellent choice for homeowners, landscapers, and gardeners alike.