Answer: You do need two varieties of some fruit trees for cross-pollination. However, in virtually all cases the two are not male and female trees, but rather both have complete blooms with male and female flower parts. Being of different genetic makeup allows pollen from one variety to successfully pollinate the other variety and vice versa.
To generalize, fruits usually requiring a second variety for cross-pollination include: apples, pears, plums, and sweet cherries. Fruits not requiring a second variety for pollination include: sour cherries, strawberries, figs, grapes, gooseberries, currants, raspberries and blackberries. Blueberries do best with at least two varieties planted for cross-pollination.
For more detailed information on fruit pollination requirements check out the following web site:
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