The best plum blossom tree variety for cultivation in the United States is the 'Shirotae' plum. This variety is renowned for its vibrant pink flowers, which are highly sought after for their beauty and fragrance. The 'Shirotae' plum blossoms are also known for their early blooming period, making them a favorite among gardeners looking to add a splash of color to their landscapes in the early spring.

The 'Shirotae' plum is favored for several reasons. Firstly, it is highly adaptable to a wide range of climates, including those with cold winters, which is beneficial for gardeners across the United States. According to a study published in the Journal of Environmental Horticulture, 'Shirotae' plum trees can withstand temperatures as low as -20°F (-29°C), making them suitable for cultivation in many regions. Additionally, the 'Shirotae' variety is known for its disease resistance, which is crucial for maintaining the health and longevity of the tree.

Furthermore, the 'Shirotae' plum tree is valued for its ability to produce a high yield of fruit, which is not only delicious but also visually appealing. The fruit is typically medium-sized, with a sweet and tangy flavor that is highly appreciated by both homeowners and commercial growers. The American Plum Society has recognized the 'Shirotae' plum as a top variety for its fruit quality, contributing to its popularity among American gardeners.

In terms of aesthetics, the 'Shirotae' plum tree has a dense, pyramidal shape, which is both visually pleasing and practical for garden design. Its dark green leaves and attractive bark add to its overall appeal. The tree also has a relatively short lifespan, typically living for about 20 to 30 years, which is a manageable timeframe for gardeners who wish to enjoy its beauty and fruit production over several decades.

In conclusion, the 'Shirotae' plum blossom tree is the best variety for cultivation in the United States due to its adaptability, disease resistance, fruit quality, and aesthetic appeal. Its early blooming period and ability to thrive in various climates make it a versatile choice for gardeners across the country.