A few days ago I overheard someone complaining about goldenrod causing her allergies. I wanted to say something but felt it was prudent to keep my mouth shut. Uninvited conversations seldom end well.
The truth is that goldenrod has very nectar rich sticky pollen. It’s highly unlikely that it would be airborne and cause someone to breathe it in. However, goldenrod is very conspicuous this time of year and has often been considered the culprit for people’s discomfort.
Ragweed grows in similar locations, is less obvious and produces copious amounts of pollen that tends to float in the air. Most likely, there’s your problem. Ragweed pollen will be with us until the first hard frost. After that, plants will soon wither and pollen release will cease. Sometimes foliar diseases destroy plants before that.
Ragweed isn’t the only plant that produces pollen that causes allergy sufferers discomfort. It’s just the most common. Generally speaking, bright colored flowers are usually not a problem. They are most likely insect pollenated and have sticky pollen.
Wind pollinated plants like ragweed are the ones that cause problems. Flowers from these plants are usually less showy, so we don’t notice them. Additionally, many of these plants produce tremendous amounts of seed, meaning problems for future years.
Pigweed and lambsquarter are heavy pollen and seed producers without showy flowers. Both are wind pollinated and cause problems for allergy sufferers. Both also make excellent cooked greens, so harvesting them before they flower can be a double win.
Some folks can ingest ragweed greens with no ill effects. I can and consider them pretty good. However, many folks with severe ragweed pollen allergies also are sensitive to the foliage. Sometimes even pulling a bunch of ragweed from flowerbeds can cause skin rashes.
Recognizing ragweed foliage could be helpful. That’s not as easy as it sounds. There are numerous species of ragweed and the only real common features are the flowers, and they aren’t very showy.
Common annual ragweed has foliage that strongly resembles cosmos except leaves of ragweed are hairier. Plants generally grow upright and can obtain heights of three to six feet. Leaves are deeply lobed and much wider at their base.
Giant ragweed leaves emerge from stems in groups of two and have three distinct pointed lobes. Stems grow very tall, often more than ten feet. They will begin to develop flowers before they get to that point, however.
Both of these should be removed from the area before they flower. Any of the dozens of other similar species should too. Some folks might wish to wear gloves and wash up afterwards. In general it’s good practice to remove any weeds before they flower. This isn’t easy, especially if you have cosmos in your flowerbeds.
It’s also a good idea to keep ragweed pollen outside if you can. Pets that travel in and out can bring large amounts of pollen into the house. People should groom pets outside which can help prevent pollen from spreading into the house and the ductwork. Your guests with pollen allergies will appreciate it.
Ted Manzer teaches agriculture at Northeastern High School.