Tree flowers, like these on an oak, produce pollen that can stimulate allergies. (Photo by Dan Gill)

For Release On Or After 05/02/14

By Dan Gill
LSU AgCenter Horticulturist

Many gardeners suffer from pollen allergies and are prone to sneezing, runny noses, watering eyes and sinus pressure headaches while working outside when pollen counts are high.

It’s hard to say if the unusually cold winter and cool spring we have had this year will have any effect on pollen. But the abundant vegetation in Louisiana commonly produces high pollen counts.

The trees that produce so much airborne pollen in early to midspring have finished blooming by now and are no longer contributing to the pollen count. But many cool-season grasses are still blooming, and some early warm-season grasses may even be blooming. Here in Louisiana, moderate to high pollen levels can stretch from March to November.

Constant exposure to hundreds of airborne pollens can turn a relaxing outdoor hobby into a sneeze-filled experience. Allergy sufferers, however, can use some simple tips to minimize their exposure to pollen. Also, gardeners can avoid and eliminate troublesome pollen-producing plants to reduce airborne pollen in their gardens.

Problem pollens

Wind-pollinated plants produce light pollen grains that are released into the air and drift in the wind. The goal is for the pollen (the male sexual cells) to blow around and eventually land on the female organs of flowers, pollinate them and produce seeds. Wind-pollinated plants are characterized by drab, inconspicuous flowers that appear in clusters, tassels or catkins. You hardly ever notice the flowers of wind-pollinated plants. Because they don’t have to attract pollinators such as insects, birds or bats to carry the pollen from flower to flower, they don’t waste effort producing colorful petals or fragrance.

Allergy problems are produced by tiny airborne pollen particles from these wind-pollinated plants. They are easily inhaled by people and can cause allergic reactions. Many shade trees such as oak, maple, ash, pecan and birch are wind-pollinated. Other wind-pollinated plants include grasses (many are in bloom now), ragweed, dock and junipers.

The good news is that the less allergenic pollen-producing plants are usually the ones that we tend to plant in our gardens with prettier, more colorful flowers. These plants are insect-pollinated, and their colorful flowers are meant to attract pollinating insects like bees. Their sticky pollen is designed to adhere to the legs and body of insects and is really too heavy to be carried by the wind. Because the pollen does not become airborne, it is rare for insect-pollinated plants to cause a reaction in allergic individuals unless they stick their nose in a flower.

Sometimes it is the attractive flowering plant that gets blamed for allergies produced by a wind-pollinated plant. Excellent examples are goldenrod and ragweed, which bloom at the same time in the fall. Goldenrod produces showy, golden-yellow flowers that are insect pollinated. Goldenrod pollen does not become airborne. Ragweed, on the other hand, is wind-pollinated and causes allergies in many people. However, its flowers are inconspicuous, and you would never notice it blooming. So goldenrod is often blamed for the “hay fever” that people suffer in late September, October and early November. But ragweed is the real culprit.

Tips for allergy-prone gardeners

Knowing how to limit exposure to problem pollens can make gardening, yard work and other outdoor activities more bearable. Keep these tips in mind to combat unnecessary exposure to pollen in your backyard.

– Avoid gardening in the early morning hours, as pollen counts are highest before 10 a.m. Likewise, pollen counts tend to rise as the sun sets.

– Wear a mask to filter airborne allergens when working in the garden, mowing the lawn or raking.

– Choose trees, plants or shrubs that are not wind-pollinated when planning to beautify your yard. Remember, the prettier the flower, typically the safer the pollen.

– Remember that pollen counts are highest on warm, sunny, breezy days and lowest on cool, cloudy, calm days or after a rainfall.

– Check yards frequently to ensure that highly allergenic weeds are not proliferating – for example, ragweed, nettle, dock, plantain, pigweed and lambsquarters. In particular, keep bermudagrass at bay; this highly allergenic plant flourishes in garden beds and lawns.

A challenge in some urban areas is a large number of vacant and abandoned properties. Lack of maintenance allows many allergy-causing plants to grow virtually unchecked. The more we can do to keep these areas mowed or cut down, the more it will help reduce pollen counts.

By all means don’t just suffer. Talk to your family doctor or visit an allergy specialist if needed. Various over-the-counter and prescription medicines can substantially reduce allergy symptoms.

Rick Bogren