What’s up with fruit pollination?
In order for your tree to produce fruit, the flowers must be pollinated. Here’s a rundown of some terms we use when discussing how best to get fruit from your plants:
Pollenizer: Any plant that produces compatible pollen for cross-pollination. Often, some varieties are bred to be especially good pollenizers, while other varieties will be bred to have better fruit.
Self-fruitful: Plants that can pollenize themselves and produce normal levels of fruit without a second plant.
Partially self-fruitful: Plants that can act as their own pollenizer, but will produce more fruit with another variety of their species nearby.
Not self-fruitful: Plants that will not produce fruit on their own. They need a second variety of their species nearby.
Dioecious plants: Some fruit species have two types of plants: one that produces pollen, and one that makes the fruit. In these cases, not only do you need at least two plants to get fruit, you specifically need to have at least one pollen-producing plant and at least one fruiting plant. Often a single pollen-producing plant will be enough for multiple fruit-producing plants. Kiwiberries are an example of this.
What about wild fruits? Wild plants of the same species are each genetically distinct and can pollenize each other—each plant is essentially its own variety. This is also true of any fruit tree grown from seed. To get fruit, you may need at least two plants of the same species, but they do not need to be different named varieties.
Why are fruit trees grafted onto rootstocks?
Many fruit trees grown from seed will not have the same traits as the parent tree, so desirable varieties must be propagated from cuttings. A tree grown from a cutting will be identical to the parent tree. Grafting the cutting onto the selected rootstock also allows us to control the size of the tree, which is good for urban gardeners.
When we know, we include what rootstock our fruit trees are grown on. You can find out more about rootstocks here: treefruit.wsu.edu/varieties-breeding/rootstocks
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If you still have questions, find a plant expert in the Fruit section.