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Goldenrod or ragweed: which one causes fall allergies

August to October

The showy yellow goldenrod blooming everywhere gets blamed for fall allergies, but its pollen is too heavy and sticky to fly. The real culprit is drab green ragweed, blooming quietly at the same time.

Why this time of year

Ragweed season in the East starts around mid-August and peaks in mid-September, exactly when goldenrod is at its brightest, so the flower you can see takes the blame for the pollen you cannot.

How to notice it

  1. Find a goldenrod plume and watch it for a minute: it is busy with bees and other insects, which is how its heavy pollen travels.
  2. Now hunt the same field edge for ragweed: knee-to-shoulder height, ferny leaves, and drab green flower spikes nobody would plant on purpose.
  3. Flick a ragweed spike gently and watch for a faint puff; one plant can release up to a billion wind-borne grains.
  4. If someone in the family sneezes through September, this plant, not the yellow one, is why.

Try this with kids: Which flower has all the bees on it, the bright one or the plain green one?

wind-pollinated plants ship pollen through the air; insect-pollinated ones like goldenrod send it by bee

Sources

  • massaudubon.orgGot allergies? Don't blame goldenrods: their pollen is heavy and sticky and can't fly through the air; the culprit is ragweed, which releases its irritating pollen freely into the wind; nothing says late summer in Massachusetts like fields aglow with blooming goldenrods.
  • extension.psu.eduGoldenrod is often blamed for seasonal allergies, but its pollen grains are large, sticky, and dense, too heavy to be carried by wind, and are carried by insects; ragweed blooms at the same time, is wind pollinated, and one plant may produce a billion grains of lightweight pollen that remains airborne for days.
  • acaai.orgRagweed usually reaches peak levels in mid-September and produces a fine-powder pollen from August into November; ragweed pollen causes seasonal allergic rhinitis, which affects as many as 25 million people in the US.
  • acaai.orgRagweed pops up throughout the East starting in mid-August; each grain can travel more than 100 miles on the wind, and one plant produces up to one billion pollen grains.

In the guide for August, September, October

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