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Goldenrod vs. Ragweed

Here are two native PEI plants, both flowering now. One gets unfairly maligned for causing seasonal allergies and the other was once the target of a province-wide elimination strategy. Meet Goldenrod (Solidago canadensis) and Ragweed (Ambrosia artemisiifolia).



I think Goldenrods are among the Island’s most under-appreciated plants. My Grandfather used to dismiss them as “those darn yellowweeds”, which is a sentiment shared by many. We have roughly a dozen different species, all native and some quite rare; our very common Canada Goldenrod is shown here (left photo).


Because they’re so conspicuous this time of year, Goldenrods get unfairly blamed for causing ‘hayfever’ allergies, when in fact they’re just innocent bystanders. Goldenrod pollen is too heavy and sticky to be carried by wind, and these plants are pollinated by insects including our native bees, butterflies, moths, and wasps. If you’re sneezing at this time of year, the cause is much more likely to be fungal spores (which are very abundant right now) or Ragweed.


In addition to being important to late-season pollinators, Goldenrod flowers and leaves are edible and can be eaten raw or dried to make a pleasant, anise-flavoured tea. The plants are proven diuretics, and Canada Goldenrod also contains quercetin, a well-documented antioxidant and anti-inflammatory compound. This plant is currently the topic of research for anti-microbial, antioxidant, anti-bacterial, and anti-fungal uses.


One final bit of botanical trivia: Goldenrods contain natural rubber. Thomas Edison began experimenting with this prior to World War 1, and the tires on the Model T given to Edison by his friend Henry Ford in 1928 were made from Goldenrod rubber. By World War 2, synthetic rubber (from petroleum) had been developed and work on natural Goldenrod rubber was abandoned.


Unlike Goldenrod, Ragweed pollen IS a major cause of seasonal allergies. It’s light, easily carried by the wind, and a single plant can produce a billion pollen grains. Roughly one in every four people is allergic to Ragweed. And unlike Goldenrod, Ragweed is a fairly inconspicuous plant that I’m betting many Islanders have never noticed. Common Ragweed (right photo) is native to PEI; we also have two non-native species, which are not common.


In 1952, the PEI Tourist and Information Bureau launched a Ragweed elimination program in an effort to make PEI a “hayfever haven”. In the first year of the program more than 40,000 plants at 126 sites were sprayed with 2,4-D. The program did have some success: Ragweed pollen counts at eight sample stations around the Island were lower in subsequent years. By the late 1950s, PEI was being promoted as Ragweed-free and a “near-perfect haven for hay-fever patients”. The Tourist Bureau even produced a special brochure promoting this (if anyone still has a copy, I’d love to scan it or get some photos for my files).


We humans are prone to confusing correlation with cause and effect. When a flower becomes very abundant at the same time your allergies kick in, it’s natural to assume it is the cause even if this is not the case. And while some people *are* allergic to Goldenrod (often those who are also allergic to latex), far more are allergic to Ragweed. I can understand why you may not want to encourage Ragweed around your home, but Goldenrods are beautiful, useful, and important additions to any pollinator garden. And both plants are interesting parts of PEI untamed!

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