The best variety of bowl lotus for cultivation in the United States is the 'American Beauty' lotus. This variety is renowned for its vibrant pink flowers and is well-suited to the diverse climates across the country. The 'American Beauty' lotus is a hardy species that can withstand a range of temperatures and soil conditions, making it a popular choice among both beginners and experienced gardeners.

The 'American Beauty' lotus is favored for its striking appearance and ease of care. According to a study published in the Journal of the American Society for Horticultural Science, this variety has a high survival rate and requires minimal maintenance compared to other lotus species. The research indicates that 'American Beauty' lotuses can thrive in water temperatures ranging from 60 to 95 degrees Fahrenheit, which aligns well with the temperate climates found in many regions of the United States.

Furthermore, the 'American Beauty' lotus is known for its ability to produce multiple blooms throughout the growing season. This feature is particularly appealing to gardeners looking to enjoy a prolonged display of color and fragrance. The American Society of Landscape Architects notes that the 'American Beauty' lotus is also highly attractive to pollinators, such as bees and butterflies, which can enhance the overall health of the garden ecosystem.

In addition to its aesthetic appeal and adaptability, the 'American Beauty' lotus is also valued for its versatility in garden design. Its large, showy flowers can be used to create focal points in water gardens, ponds, and even indoor water features. The versatility of this variety makes it a top choice for gardeners seeking to add a touch of elegance and sophistication to their outdoor spaces.

In conclusion, the 'American Beauty' lotus is the best variety of bowl lotus for cultivation in the United States due to its vibrant color, hardiness, adaptability, and ease of care. Its ability to produce multiple blooms and attract pollinators further solidifies its status as a preferred choice among gardeners looking to create a stunning and sustainable water garden.