Spring is here, though the calendar and a certain groundhog may disagree. In the desert, this time of year is associated with floral blooms. Many species grow and reproduce in these cool months, but only when enough moisture is present. In dry years, many seeds remain ungerminated in the soil; in wet years, growth proceeds unchecked. Even perennial species like cacti grow more in cool and wet years. This strategy of temporal drought avoidance and rapid growth enables many species to persist in an environment that is very harsh for most of the year. Below you can see one small cactus putting out flowers – probably for the first time in its life!
Rain in the desert is erratic. Wind, proximity to mountains, time of day – so many things determine precipitation patterns. Some places have had wet winters, while others have had very dry ones. Near Tucson, the poppies and lupines are in full color – but in the Dragoon mountains, seen below, all is dry and dead. Many of the seeds here will not germinate this year. It is a risky game for plants, as they must integrate environmental signals to guess if future conditions will support their growth for long enough to complete a reproductive cycle. Each seed can only play this game once!