From the CO2Science Archive: Eastern Purple Coneflower, aka Echinacea purpurea, a flowering perennial, furnishes the active ingredient in some herbal remedies and is a nice late-summer display for our gardens. And getting nicer because in 2007 four experiments showing an extra 300 ppm yielded a remarkable 191.5% increase in plant growth. So if you find echinacea makes you feel better when you are sick, just remember your CO2 helps it feel better all the time.
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Effect of 300 ppm extra CO2 on Eastern Purple Cornflower
18 Jun 2025 | Science Notes
Apparently the idea of CO2 increasing plant growth is lost on some people. According to [this CNN piece](https://www.cnn.com/2025/06/18/climate/food-crops-heat-rain) climate change will add famine to all our other woes as crops fail.