Dimensions
187 x 226 x 19mm
In the past ten years, allergy and asthma rates have continued to increase dramatically around the world. An estimated 50 million Americans (1 in 5) suffer from asthma and allergies--more than diabetes, heart disease, cancer, and Alzheimer's. Thomas Ogren's innovative system is based on the fact that only male plants, which are over-planted in gardens and civic landscapes, produce pollen. By raising public awareness and by removing or replacing troublesome plants in your yard with pollen-blocking females and other pollen screens, allergy-sufferers can reduce or eliminate their symptoms. More than 3,000 plant listings are included and graded 1 to 10 according to OPALS, the plant-allergy ranking system created by Ogren and now used by the United States Department of Agriculture.