How to Grow a "Cool Planet" Garden
Gardeners are inherently in touch with their place. That is why many gardeners have been the first to notice changes that may be linked with global warming.
Changes in Hardiness Zones
The National Arbor Day Foundation has recently updated its hardiness zone map to reflect recent trends. Click here to see a map showing the differences in United States Department of Agriculture hardiness zones between 1990 and 2006. These zones reflect a warmer climate.
The National Resources Defense Council (NRDC) has put together an interactive map showing which state trees and flowers may no longer grow in their "home states" as the effects of global warming increase.
Global Warming May Aid Noxious Weeds
Noxious weeds, including poison ivy and ragweed – the pollen of which is a leading cause of allergies – will flourish as levels of CO2 in the atmosphere increase. At an experimental plot where scientists can precisely control the concentration of carbon dioxide in the air, Duke University researchers discovered that when exposed to higher levels of CO2, poison ivy goes haywire. The plant not only grew faster, but produced a more noxious form of its rash-causing chemical – in other words, a more poisonous poison ivy. The study found that poison ivy grew about 149 percent faster in an environment with a higher concentration of CO2. At the same time, urushiol – the chemical in poison ivy that causes rashes and sometimes more serious symptoms – was found to be about 153 percent more concentrated per leaf. And rising CO2 seems to favor the growth of weeds above the growth of plants we’d prefer to see succeed.
What You Can Do
Create a "cool planet" garden. NRDC has teamed up with expert gardeners from the Garden Club of America to develop the Gardener's Guide to Global Warming, a useful guide that brings global warming solutions to your own back yard. Click here to download a copy. [PDF]
1Mohan, J.E., Ziska, L.H., Schlesinger, W.H., Thomas, R.B., Sicher, R.C., George, K., Clark, J.S. Biomass and toxicity responses of poison ivy (Toxicodendron radicans) to elevated atmospheric CO2. Proceedings of the National Academy of Sciences of the United States of America 103 (24): 9086-9089 (June 2006)
