Desert annuals, like wildflowers, are adapted to the arid environment in many different ways. These include thick, waxy coverings on leaves and stems that reduce exposure and thus evaporation loss while the plant transpires or "breathes"; small leaves that receive less solar radiation; and deep taproots to reach further into the soil or shallow, widespread roots that absorb surface water quickly. Despite these adaptations, most desert wildflowers avoid drought and heat by surviving as seeds or bulbs stored in the soil, sometimes for decades. These seeds will only germinate after significant seasonal rainfall, so wildflower growth in Montezuma Castle is highly-variable year to year. April and May are generally the best months to see wildflowers, then again in early fall if there are a lot of summer monsoons. Some desert plants take advantage of the nights cooler temperatures to flower. These evening-blooming plants include evening primrose, datura, sand verbena, and yucca.