Madrean Archipelago

The Madrean Archipelago reaches into the United States only in southeastern Arizona and the boot heel of New Mexico, the sky-island country around Sierra Vista, Nogales, and Bisbee. Grassland and oak woodland climb the slopes between desert basins, fed by a strong summer monsoon, and the mix of temperate and subtropical species makes it one of the richest places for pollinators in North America. Natives such as deer grass, blackfoot daisy, and birchleaf mountain mahogany match that pattern of dry spring and wet late summer.

Conditions: Rocky slope soils between desert basins, 12–20 inches of precipitation dominated by the summer monsoon, mild winters with occasional frost.

Cities and areas: Sierra Vista, Nogales, Bisbee, Douglas, Benson, Patagonia.