Timothy Grass
Timothy grass is the predominant allergen seen in Mesa, Telluride, Aspen, Crested Butte and with people who ranch up on the Mesa, probably starting to grow around 7,000 feet.
Orchard Grass
In lower elevation regions of Western Colorado (<8,000 ft), orchard grass is the predominant wild grass growing and releasing pollen.
Bermuda
Bermuda grass is is prevalent in Grand Junction and Delta, but becomes less common at elevations equivalent to Montrose or higher.