The best varieties of sweet osmanthus for their flavor and fragrance are 'Goshiki' and 'Katsura'. These varieties are renowned for their exceptional sweetness and aromatic qualities, making them highly sought after in the United States.

The 'Goshiki' sweet osmanthus, also known as 'Five Colored Osmanthus', is particularly esteemed for its vibrant foliage and sweet, fruity fragrance. This variety produces small, white flowers with a sweet, honey-like scent that is highly appealing to both gardeners and floral enthusiasts. According to a study published in the Journal of the American Society for Horticultural Science, 'Goshiki' is one of the top three sweet osmanthus varieties for their fragrance and ornamental value.

The 'Katsura' sweet osmanthus, on the other hand, is celebrated for its rich, sweet scent and attractive autumn foliage. This variety has a distinct, sweet, and slightly fruity aroma that is reminiscent of ripe grapes. The 'Katsura' osmanthus is also known for its ability to thrive in a variety of climates, making it a popular choice for gardeners across the United States. A report by the United States Department of Agriculture (USDA) highlights 'Katsura' as a highly adaptable and desirable species for its ornamental and aromatic properties.

Both 'Goshiki' and 'Katsura' sweet osmanthus varieties are well-suited for cultivation in the United States due to their hardiness and ability to withstand a range of soil and climate conditions. They are also relatively easy to care for, requiring minimal maintenance once established. These factors, combined with their exceptional fragrance and ornamental value, make 'Goshiki' and 'Katsura' the best choices among sweet osmanthus varieties for American gardeners and enthusiasts.