Fall Allergies and the Ragweed Plant

Common ragweed can compete with crops and cause yield losses. Some aggressive herbicides may work against common ragweed, but will also affect nearby plants.

Ragweed can be overgrown by turf grass and other perennial plants that grow every year. Farmers often plant small grains in rotation and overseed with clover to suppress ragweed.

Photo by burntchestnut 

Ragweed is only behind mold in causing allergic symptoms. The ragweed flower normally blooms from early July until the weather gets cold. One ragweed plant can release up to a billion pollen grains.

The pollen grains are microscopic – approximately 20 microns in diameter (or 1/25,000th of an inch). Ragweed pollen is spread by wind, so it’s easily ingested or inhaled and even brought in on clothing or your pet’s fur.

Ragweed attracts many insects which have high protein content. Pheasant and quail hens can eat the insects and also bring them to their chicks.

Ragweed seedlings come up from May through July. The flowers are formed from July to September, and the seeds mature around August until the first frost. The seeds give wild birds something to eat during the cold winter months.

Planting ragweed in fields has helped to increase quail and pheasant populations. Plant it during fall or winter. After it grows, disk the field each year. When the weeds aren’t as abundant, seed again.

Photo by Burntchestnut.

Chemical spraying will usually get rid of ragweed quickly, but you probably will have to use an aggressive herbicide in order to kill it.

Remember that herbicides kill all other vegetation it touches, too, and can run off and affect other neighboring fields and lawns.

Mowing is another way to control ragweed. Mow it continuously because ragweed will regrow in about two weeks if there’s even as little as a half inch of stem left. Keeping the ragweed mowed will also prevent it from flowering and later making seeds.

Uprooting ragweed is another option and should be done in late spring before it flowers and before it’s had time to develop strong roots.

Cutting and burning ragweed works best because the stems are killed and the plant can’t grow back. But burning does pollute the air and there’s always the danger of an out-of-control field fire. Cut down the ragweed and burn it only after the stalks have dried.

Photo by Burntchestnut