With allergy problems reaching alarming, epidemic levels, horticulturist Tom Ogren sets out to investigate the role that urban landscaping plays in this urgent health crisis. What he discovered was startling: The vastly disproportionate cultivation of all-male plant varieties produces large amounts of intensely irritating airborne pollen. This extensively researched, comprehensive, plant-by-plant reference alerts gardeners and helps them make landscaping choices that can drastically reduce their exposure to harmful allergens. Complete with alphabetical entries of basic planting information, growing zones, and allergy ratings.