What fruit trees need another for pollination?
Peaches are commonly self-pollinated. In fact with many peach trees, the fruit has been pollinated even before the flower reaches full maturity, even before it opens all the way. Now that’s true for most of our standard varieties. But some of the old varieties, like Bell of Georgia, are pollen sterile. So in those cases you will need another variety for pollination.
Both apples and pears are both strongly cross pollinated. And that means you need to plant two apples or two pears, with similar chilling requirement so that they bloom at the same time. That way, the pollen is available for insects to transfer from plant to plant.
Plums, well that depends. Some of the plum varieties that are adapted best to Central Texas, such as Methley or Santa Rosa, are self-pollinating. So you don’t need to have another plum. A single plum will bear fruit.
But many of the standard varieties especially some of the higher chilling ones, like Morris and Ozark Premier, those are strongly cross pollinated. So in the colder parts of the state, where there is higher chilling hours, those two plums are ideal to plant next to each other because they do bloom at the same time.
Grapes are commonly self-pollinated. In fact grapes are wind pollinated. So really there is not much you need to do to set fruit on grapes other than to simply let them bloom normally.
One of the crops that is commonly misunderstood are pecans. Pecans are strongly cross pollinated. So you need another variety. There’s protoginus that bears its female flower first. Or protanderist that bears pollen before the female is receptive.
Now if you’re in an isolated part of West Texas it is important to plant one of each so that there is pollen transfer. But here in Central Texas we have so many native pecan trees that you really don’t have to worry about it. There’s enough pecan pollen flying during bloom of pecan trees for all trees to be pollinated. So a single tree will bear pecans for you.