We know that plants must be pollinated in order to reproduce. However, the method of pollen distribution varies depending on the plant. Each spring, we get a good idea of one method of pollen transfer when everything outdoors is covered in green powder: sidewalks, lawn furniture, window sills, and our cars. And those of us with pollen allergies are well aware of when pollen is in the air.

Wind pollinated trees are the culprits, releasing copious amounts of small, lightweight pollen into the wind.

Wind pollinated plants do not waste energy producing flowers with strong fragrances or nectar to attract pollinators. Instead, the focus is on efficient pollen production and dispersal that ensures pollen finds female flowers for successful fertilization. Releasing large amounts of pollen compensates for the randomness and inefficiency of wind dispersal.

Trees that are wind pollinated include oak, birch, walnut, hickory, elm, cottonwood, poplar, and cone-bearing trees: white pine, spruce, fir, and cedar.

Grasses and weeds are also wind pollinated. People often blame goldenrod for hay fever because it blooms at the exact same time as the real culprit, ragweed. It’s an easy mistake since goldenrod's bright yellow flowers are highly visible in bloom while allergy-causing ragweed flowers are inconspicuous.

However, this plant releases millions of lightweight pollen grains that can drift in the breeze for miles, triggering allergies for millions of people every year. Remember, wind pollinated plants don’t bother producing showy flowers to attract animal pollinators.

Showy goldenrod is not the cause of hay fever. Its pollen grains are much too heavy and sticky to be carried by the wind. The pollen does however, cling to animal pollinators.

Self-pollination. Plants that self-pollinate have both male and female flowers. These plants include many vegetables such as beans, cabbage, and carrot, and many stone fruit trees such peach, plum, and cherry.

While these plants do not strictly require bees to reproduce, native bees that visit these flowers transfer pollen efficiently, which significantly improves yield and quality.

Animal pollination. About 75% of flowering plants rely on animals to transfer pollen. While foraging for nectar, bees, flies, butterflies, moths (night-shift pollinators), beetles, birds, and Western bats pick up pollen grains on their bodies. The pollen dusts and fertilizes the next plant they visit.

Because plants need animal pollinators to carry their pollen, they evolved specific characteristics — unique shapes, sizes, and colors — to attract the pollinator who can most effectively pollinate them. Bees are our most successful pollinators because, unlike other animal pollinators, bees intentionally visit flowers to collect pollen for their offspring. Pollen is an essential source of protein and amino acids for developing bee larvae.

Native bees, of which there are 340 species in Connecticut, are rock stars! They include bumble bees, squash bees, and mason bees, to name just a few. Native bees are very important to agriculture. As major pollinators of tree fruits, berries, and vegetables, they add an estimated $3 billion worth of crops annually to the US economy.

When native bees visit flowers, their bodies get covered with pollen. Moving from one flower to another, worker bees brush flowers with pollen for effective cross pollination. Bumble bees and carpenter bees also have the ability to “buzz pollinate” — an adaptation that allows them to shake pollen loose from flowers that other bees cannot access.

Blue orchard mason bees are masters of “belly pollination,” preferring to carry pollen on their abdomens. This belly-flopping from flower to flower is very effective.

European honeybees carry little pollen on their bodies, preferring to groom pollen and nectar into a paste. This “neatness” makes honeybees less effective at transferring pollen. Belly-flopping mason bees pollinate 100 times more flowers than honeybees do in a single day. And according to Xerces Society of Invertebrate Conservation, “Flowers pollinated by native bees will have larger and higher quality of fruit.”

Water pollination is an extremely rare method of pollination. Only about two percent of aquatic plants rely on currents to carry their pollen grains to another flower. But just as with terrestrial plants, the majority of aquatic or bog plants are pollinated by bees and flies. So, while some plants employ other methods of pollination to reproduce, insects and other animal pollinators are most valuable for the pollination services they provide, creatures we simply cannot live without.

My Backyard Habitat is published monthly in cooperation with The Newtown Bee by Protect Our Pollinators. For more information or to reach us, visit propollinators.org.

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