Pollination is the transfer of pollen from the male part of a flower (the stamen) to the female part of a flower (the pistil). Fertilization then occurs in the ovary when a sperm cell from a pollen grain unites with an egg to produce an embryo. This then develops into a seed. After fertilization, the ovary develops into a fruit with the seed(s)inside.
Most kinds of plants have blossoms that are incompatible with their own pollen, and must therefore be cross-pollinated with pollen from another plant individual. The pollinator that does the deed can be an animal such as an insect, a bat, or a hummingbird, or it can be the wind aka anemophily.
Many of our most important crops are wind pollinated – corn, wheat, rice, oats. Also, many kinds of trees – pines, oaks, maples. Some of our favorite nut trees depend on the wind for pollination – pecans, pistachios, hickories, black walnut, butternut, hazelnut, English walnut. Chestnuts and coconuts can go both ways – wind and insect pollination. Read more about the Pros and Cons of Different Nut Trees to determine which one is right for your landscape.
Virtually all conifers and grasses and some 15% of flowering plants are wind pollinated.
Flowers that are wind pollinated need not be fragrant, showy, nor produce nectar, since they don’t have to attract animals to do their bidding. Wind pollinated flowers often have long stamens that put the pollen grains out where the breeze is strongest.
Many wind pollinated trees have flowers that hang down (called catkins) so that the slightest breeze will release the pollen grains. Most have flowers that come out before the leaves which would otherwise obstruct the wind. The pollen receiving structures are often feathery, like a net, to capture pollen grains sailing by.
What size are the pollen granules?
Pollen that is moved on the wind is very different from pollen carried by birds, bees, or butterflies. Since the odds of a windblown pollen grain actually landing on the appropriate flower are minuscule, wind pollinated plants produce LOTS of pollen. One grass flower can produce ten million pollen grains. A wind pollinated tree produces billions of pollen grains. Most of them go to waste, never landing on their target.
Pollen grains that depend on the wind are tiny compared to those that are moved by animals. So tiny, in fact, that they can enter a person’s nasal passage and cause an allergic reaction (hay fever).
Wind pollinated crops (pecan trees and corn for example) should be planted in blocks rather than single rows, to maximize the chance of a pollen grain finding its target in shifting winds. Read more about Pollination in Fruit Trees and in our Pecan Grow Guide.