The most abundant plum blossoms in a city in the United States can be found in Washington, D.C. The Tidal Basin, located near the National Mall, is renowned for its spectacular display of cherry blossoms, which are closely related to plum blossoms. Each spring, thousands of visitors gather to witness the blooming of these delicate flowers, which attract both locals and tourists alike.

The reason Washington, D.C. is home to such a significant number of plum blossoms lies in the city's extensive horticultural history. The Tidal Basin was originally designed to manage the Potomac River's tidal flow and was later transformed into a public park. The National Park Service has planted numerous cherry and plum trees along the basin, creating a picturesque landscape. According to the National Park Service, there are over 3,700 cherry trees and approximately 1,200 plum trees in the area. The cherry blossoms typically peak in late March or early April, while the plum blossoms follow shortly thereafter, offering a continuous display of spring beauty.

Data from the National Park Service indicates that the Tidal Basin's plum blossoms are particularly impressive. The park's collection of plum trees includes various species, such as the Japanese plum (Prunus salicina) and the Korean plum (Prunus mume). These trees are known for their vibrant pink and white blossoms, which create a stunning backdrop against the historic monuments and buildings in the area. The National Cherry Blossom Festival, which celebrates the blooming of the cherry blossoms, also highlights the beauty of the plum blossoms, drawing attention to their significance in the city's springtime landscape.

In addition to the Tidal Basin, other areas in Washington, D.C. also feature plum blossoms. The United States Botanic Garden, located on the National Mall, houses a collection of over 4,000 plants, including various species of plum trees. The garden's extensive collection of ornamental plants and trees makes it a popular destination for those interested in botany and horticulture.

Overall, Washington, D.C. stands out as the city with the most plum blossoms in the United States, primarily due to the extensive plantings in the Tidal Basin and other public spaces. The combination of historical significance, horticultural expertise, and the beauty of the blossoms make it a must-visit destination for anyone interested in experiencing the splendor of spring in the nation's capital.