For the most part, cherry trees are not self-fertile and do require pollen from another cherry tree to produce fruit. Plant at least two varieties in the area to ensure a good crop. A few sweet cherry trees are self-fertile and do not requires external pollen. These varieties include Lapins, Glacier Stella, Sonata, Sweetheart, Skeena and others.
There are also sour cherry varieties. Sour cherry trees are self-fertile and do not require external pollination. Sour cherries can also be used to pollinate sweet cherries.