Ragweeds are in the Ambrosia genus in the aster family. There are about 50 species of ragweed. Most grow in the desert areas of the American Southwest and Mexico. Some species have been spread around the world, where they are now invasive species. The common name is based on the fact that the leaves may look ragged. The genus name of Ambrosia means "food of immortality." The two most common species are the common ragweed, Ambrosia artemisiifolia, and the giant ragweed, Ambrosia trifida. Artemisiifolia means that the leaves look like leaves of plants in the genus Artemisia, and trifida indicates the leaf often has three lobes.
Some ragweed species are annuals, some are perennials and some are shrubs. The two most common ragweeds are annuals that grow in poor soils in full sun to part shade and don't need a lot of rain or fertilizer to grow well. They often grow where other plants don't, such as along railroads or in gravel pits. They can be seen growing right next to each other. Common ragweed grows up to 5 feet tall, and giant ragweed can grow over 15 feet high.
A single ragweed plant can produce over a billion pollen grains. The pollen has been recorded over 2 miles high and over 400 miles out to sea. The male flowers are on tall spikes, while the female flowers are at the bottom of the spike or down among the leaves. The seeds are small burs that can cling to animals or machinery, or even be washed downstream.
The main reason anyone pays attention to such a bland plant is that millions of people have allergic reactions to the pollen. About half of all pollen-related allergies are caused by ragweed. You may be born with the allergy, or it may develop later.
Proteins and other chemicals on the pollen cause the body to react and produce histamines. The allergic reaction then becomes a runny nose and an itchy and swollen nose, eyes and mouth.
Ragweed allergy sufferers can also develop oral allergy syndrome. They may develop allergic reactions to foods such as bananas, beans, celery, cucumbers, kiwi, melons, potatoes and zucchini. There are a variety of treatments for these allergies, so see a doctor for help.
Since these plants are so harmful to so many people, how do we get rid of them? In some places, ragweeds are becoming resistant to herbicides, but herbicides are still a useful control method for many people. Ragweeds grow back quickly when mowed or chopped down, but preventing them from producing flowers is beneficial. Since they are annuals, they will die at the end of the season. Common ragweed can still bloom under the height of lawn mower blades. Digging them up before they start blooming helps kill the plant and helps prevent allergies, and while labor-intensive, it may be the best control method.
Ragweeds may not be completely bad. They are being used to remove heavy metals in industrial waste sites. There is evidence that ancient peoples ate giant ragweed seeds. They have more protein than other grain crops, and they produce a very nutritious oil. The crushed leaves may be able to relieve the sting and itchiness from bug bites.
And remember, ragweeds have green flowers, while goldenrods have yellow flowers. While they bloom at the same time and even the same locations, don't blame the pretty goldenrods for your allergy symptoms.
I also made a video about ragweed on the Greener View YouTube channel if you want more information.
DIST. BY CREATORS.COM
View Comments