The McDowell Sonoran Preserve is in the Arizona Upland subdivision of the Sonoran Desert, the highest and coldest part of the desert. Trees are common on rocky slopes and in washes, with saguaros also present on the slopes. It is subject to occasional hard winter frosts which restrict some desert plants from growing here, but the McDowell Mountains provide many microhabitats which help increase species richness.
Desert plants use one of three basic strategies to adapt to the arid climate. Succulence – the ability to store water in fleshy leaves, stems or roots in compounds from which it is not easily lost – is characteristic of all cacti, agaves, aloes. Drought tolerance – the ability to withstand dessication for months or even years without rain – is characteristic of many desert shrubs such as creosote bush and brittlebush. Drought evasion – avoiding unfavorable conditions by growing and blooming only when specific environmental conditions are met – is characteristic of many desert annual wildflowers.
For a list of plants known to occur in the McDowell Sonoran Preserve, click here.