Mountain Cedar and Eastern Red Cedar
"There are vast populations in central Texas, literally hundreds of thousands of acres are covered with mountain cedar trees. It is a major, major allergen there," says Estelle Levetin, chair of the Aerobiology Committee of the American Academy of Allergy, Asthma & Immunology and professor of biology at the University of Tulsa. The severity of cedar allergies in that region has spawned a movement, "People Against Cedars," to control the spread of the tree. If you live on the East Coast, you may be sensitive to its close relative, the Eastern red cedar (pictured above).
When does it peak? Mountain cedar: December through March; Eastern red cedar: February through April
Where does it grow? Mountain cedar grows in rocky, dry soil in the Southwestern United States (mainly Texas, southern Oklahoma, Arkansas and northern Mexico). Eastern red cedar prefers moist soils and can be found in states on the East Coast and in the Midwest.