Sweetheart has all the characteristic flavour elements of a good sweet cherry, predominantly sweet, but not at all sugary, with an underlying hint (no more than that) of bitter sharpness. The flavour is arguably richer than is usual amongst cherries. To get the best flavour, pick when fully ripe and eat immediately. We think all sweet cherries are best when eaten slightly cool, but not chilled.
Sweetheart is also self-fertile, and ripens quite late in the cherry season. Another unusual characteristic is that the picking period is longer than most, because ripening is uneven - meaning you don't get the inevitable glut which is a feature of other varieties.
Horticultural characteristics of Sweetheart cherry trees
Sweetheart is a precocious sweet cherry, and starts to bear fruit relatively young - you may get fruit within a 2-3 of years of planting, whereas most cherries will start to bear fruit after about 3-4 years.