Spring allergies are nothing to sneeze at, but gardeners can also face allergy challenges in the fall. One of the biggest culprits in the autumn landscape is Ambrosia artemisiifolia, otherwise known as ragweed.
Ragweed comes into bloom in August and continues to bloom throughout the fall, sending millions of pollen grains into the air. Gardeners may have eliminated ragweed in their landscapes, but the plant is very common along roadsides, edges of farm fields and in vacant lots. It seems there’s no escaping it completely. Its pollen is so small and lightweight that it can travel hundreds of miles in the wind.
Goldenrod, a member of the genus Solidago, often gets the blame for fall allergies. Goldenrod is a beautiful native perennial that also makes a wonderful ornamental plant in the garden. It blooms at the same time as ragweed but is showier. Because ragweed flowers typically go unnoticed during allergy season, goldenrod blooms are bright yellow and stand out, leading to goldenrod being blamed for fall allergies. However, the pollen of goldenrods is much larger and heavier than ragweed, and is carried by bees, butterflies and other pollinators rather than the wind. Goldenrod is a great plant for a butterfly garden, but an unlikely culprit for fall allergies.
What can a gardener do about ragweed? Unfortunately, the pollen grains are so small that masks aren’t very effective at limiting exposure to ragweed. But, for gardeners who are sensitive to other allergens, such as mold, wearing a mask while raking leaves or doing other yard work in the fall would be beneficial.
Another strategy is needed for ragweed. While it’s impossible to avoid ragweed pollen completely, try to limit garden work to times when pollen counts are low. During ragweed season, pollen levels are lower in the evening. Also, after working outdoors, take a shower and wash your hair. At the very least, change clothes.