It is the unwelcome interloper, an unsightly plant and the single biggest cause of annual epidemics of hay fever. For some, ragweed pollen will even trigger serious respiratory distress. Allergic Living gets to the root of ragweed and the ways to beat it.
Symptoms of an allergy to ragweed range from mild irritation of the eyes and a runny nose to completely congested sinuses; itchy eyes, mouth and throat; and sleeping problems, accompanied by fatigue and irritability.
Ragweed can provoke asthma. It is also linked to ear infections in children and sinusitis (bacterial infection of the sinuses) in adults. However, skin reactions to ragweed are rare.
The Where of It
Though there are dozens of varieties of ragweed, two are mainly responsible for the sneezing and weeping of allergic rhinitis: common ragweed (Ambrosia artemisiifolia) and giant ragweed (Ambrosia trifida).
In the United States, ragweed cuts a swath through central and eastern states from north to south. In Canada, Ontario and Quebec are hardest hit by its pollen. In both countries, the coasts are mainly clear of it.
Ragweed thrives during dry, hot summer weather. While most of us complain about clammy and rainy days, high humidity (over 70 per cent) makes it more difficult for the plant to release pollen.
Know the Enemy
Common Ragweed: An annual, it grows erect and as tall as 5 feet (1.5 meters). Lower leaf branches are opposite each other, but begin to alternate higher up the plant. The leaves are long and compound, with deeply toothed divisions on each leaf. Flowers are in spikes of small, greenish yellow florets, numerous and not showy.
Giant Ragweed: The weed lives up to its name, reaching as high as 15 feet (4.5 m). Its stems are multi-branched and hairy, with the leaves opposite, except on smaller branches.
The leaves are large, as rough as sandpaper, rounded and shallowly toothed. Flower heads are similar to common ragweed except the female head is larger. This is an annual as well, and both plants only reproduce by seed.
The Pollen: Flowers begin appearing in June, but don’t release pollen until the tail end of July, with pollen saturating the air from August through October. One plant will produce one billion pollen grains per season. Only the first frost will kill ragweed.
How to beat the Weed
1. Pull out ragweed in and around your property by the end of July. This prevents flowering and the spread of its harmful pollen.
2. Remove or mow down ragweed plants wherever you see them. Seeds can survive for 40 years, so eliminating the weeds is crucial.
3. Speak to your allergist about treatment options and develop a plan of action before allergy season hits.
4. Check pollen forecasts, and plan outdoor activities for days when counts are low.
5. Minimize time outdoors during the middle of the day, when counts are the highest.
6. Keep pollen out by closing doors and windows, and using air conditioning and HEPA air filters.
7. Wash hands frequently; take a shower and change clothes after being outside.
8. Do not hang laundry outside; it will collect pollen.
Next: Relief through medicine