Accessibility. With the annual rainfall of the desert region near Lakes Mead and Mohave less than 6 inches a year, it might be supposed that only a few hardy plants could exist under such rigorous conditions. On the contrary, however, the desert has vast numbers of flower species. Favorable rains in early spring transform the seemingly bare slopes and washes into a mass of color. Without these beneficial spring rains, the seeds lie dormant until better conditions exist.