As a comment about Beach Plum (Prunus maritima)
Color may vary from pure white to pink. The USDA plant guide pdf does have photographs showing "An example of the degree of variation of pure white to pink flowers displayed by beach plum shrubs." It states: "The immaculate white of the flowers develops a pinkish hue upon successful pollination usually achieved through the service of wild bees, but other pollinating insects may perform the task as well (Miller, 2002; Bailey, 1944)."
The Dave's Garden link has a list of cultivars and their merits, but I have only seen the unnamed beach plums available at local centers. I bought this pink shrub as a pollinator for my existing shrubs as an article in Dave's Garden indicates that shrubs that are very closely related may not cross-pollinate successfully. Whether it was pink due to natural variation or pink due to successful pollination is yet to be determined. Fruit taste is variable, too, so I will also have to be patient to test this. 🙂
On fruit color:
"The glaucous fruit produced usually ranges in color from a bluish purple to dark purple. Although less common it may also be brick red or on rare occasions yellow (Clark et al., n.d.). "
In my state of Maine, this is a monitored native species of special concern. It is native to sand dunes and prefers full sun. " Habitat
The wild beach plum's environment is characterized by low-nutrient and low-water-holding soil, high winds, blowing sand, unstable substrate and high salt levels. Under such seaside conditions, the plant grows very slowly and does not bear fruit regularly. The beach plum is not limited to sandy soil, it may be planted in any fertile, well drained soil. Its growth in such soil will be more vigorous and we believe crop size may be improved. Full sun is required for fruit production."