Purchase pollen so you can get started. Look for pollen from the same type of tree but a different variety. For example, if you need to pollinate an apple tree, you want apple pollen but not for the same variety of apple that you have. Since you have a short window to pollinate trees, get the pollen in advance.
Wait for the flowers to open. In general, flowers are receptive to being pollinated 12 to 72 hours after they are open, according to Firman Pollen Company. When flowers are receptive, you should see some natural pollen on the blossom; flowers that are no longer receptive have no natural pollen left.
Dip a small paintbrush into your jar of pollen. Tap the brush against the side of the container to shake off extra pollen.
Touch the brush to a flower to transfer pollen, thus pollinating the bloom.
Continue pollinating fruit flowers like this, reloading your brush with pollen when you no longer see pollen on its bristles. Pollinate flowers every 12 inches so you don't overload the tree.