Why Do Most Flowering Plants Not Pollinate?

Methods of Pollination

• Plants, such as corn and pine trees, that produce lightweight pollen, release their pollen into the wind which carries it to other plants, through the process of wind pollination. Other flowering plants have heavier pollen and require insects or birds to move the pollen. Honeybees are the most important pollinators, although butterflies, moths, bats and birds may also play a role. Some flowering plants, such as tomatoes, have flowers that contain both the male and female parts. These plants are pollinated by wind that knocks the pollen free. Squash, pumpkins and melons produce both male and female flowers on the same plant and are pollinated by bees. The females are identified by a small bump at the base of the flower. Many trees are either male or female, while apple trees and other fruit trees require a pollinator, or another compatible tree, to pollinate and produce fruit.

Problems

• Plants may fail to pollinate for a variety of reasons. Vegetable plants, such as tomatoes, squash, peppers and eggplants, may drop their blossoms during very hot or cold weather, eliminating pollination. Drought stress or very rainy weather can also inhibit pollination. Bee populations have been declining in recent years, due to a loss of habitat and food sources, as well as overuse of pesticides and herbicides.

Consequences

• Over 150 food crops in the U.S. alone rely on honeybees for pollination, including fruits, vegetables, nuts and oil crops. Worldwide, honeybees pollinate exotic crops, such as bananas and even chocolate. Honeybees are essential to maintain diverse and abundant food sources for humans, as well as for animals.

Solutions

• Plant a variety of flowering plants in your yard to provide food sources for butterflies, birds and honeybees. Select plants with different blooming times to provide a food source throughout the summer. Avoid using pesticides and herbicides in your garden when possible and apply them in late afternoon or evening, when fewer bees are active. Use liquid pesticides over granular ones, which can collect on a honeybee's body to be taken back to the hive, potentially poisoning many bees.

Hand-Pollination

• Help squash, tomatoes and pepper plants along through hand-pollination. Brush the anther of a male squash, melon or pumpkin with a fine paint brush to collect some pollen. Then gently brush the pollen in the female flower to distribute the pollen. Shake tomato and pepper plants lightly to distribute pollen.