Is it goldenrod or ragweed?
Knowing the difference between goldenrod and ragweed can help people avoid allergies ... not to mention unnecessarily removing native goldenrods (pictured in the photo above).
Ragweed
Minnesota is home to common, western and giant ragweed. All have lobed leaves of varying sizes and branching stems.
Ragweed images courtesy Wikimedia.
Ragweed flowers are produced both at the stem tips and at the upper leaf bases: the male flowers – located at the tips of the stem – produce copious pollen, while the female flowers are small, greenish, and non-descript. These plants can grow in clusters or singly.
While common and western ragweed can grow up to 4 feet tall, giant ragweed can reach heights of 15 feet. This said, ragweed is very commonly found mowed to just a few inches high as it is common in many lawns, alleyways, etc.
Goldenrod
There are over 45 species of goldenrod in Minnesota. While it can be challenging to tell them apart, differentiating them from ragweed is relatively straightforward once you know what to look for.
Goldenrod (above) attracts an extensive list of insects including native and European bees, an amazing variety of moth, butterfly, beetle, beneficial wasp, leaf hopper and other species.
These single-stemmed plants have unlobed, lanceolate leaves, arranged alternative on the stem. Leaves are often densely packed, giving them a slightly whorled appearance. Their flower clusters occur in many forms but are always at the top of the plant. Many species’ flowers occur in spikes or flat-topped clusters.
Ragweed more likely to trigger allergies
Ragweed’s small flowers are not showy or brightly colored (those characteristics attract pollinators). Instead, ragweed is primarily wind-pollinated, meaning that the plants rely on wind to disperse their pollen. They produce massive amounts of tiny pollen to be carried in the breeze.
Goldenrods are primarily insect-pollinated. Their showy golden flowers attract pollinators like bees and other insects. They also produce less pollen because they don’t have to rely on wind to take it to far-off plants. Their pollen is also comparatively large and heavy, so it stays near the plant.
While it is certainly possible to be allergic to goldenrod, most people would need to touch the plant or put their face near it to get pollen into their nose to trigger allergies.
Many people will mistakenly remove goldenrods from their properties to avoid allergies, this is usually ineffective for allergy reduction. If left alone, some goldenrod species provide important food sources for native pollinators.
Many Minnesotan allergy sufferers tend to find relief in the northern part of the state, where goldenrods are plentiful but ragweeds are uncommon. So the next time you start noticing your allergies kicking in, look around. Showy goldenrod may catch your eye, but it could be a less showy and more common plant triggering watery eyes.