Editor’s note: This article was originally printed in the May 2010 issue of the Newsletter for Members. The accompanying table of flowering times has been updated for 2015.
The second half of spring, that is to say, April and most of May, is not for the timid. The perennial plants that flower and fruit during these late spring months are case-hardened desert dwellers that never ask for a break from the heat and wouldn’t get one even if they did. They have no desire to be the wimpy annual wildflowers that germinate in the fall and spend a couple of leisurely winter months growing fatter each day before conveniently flowering and completing their life cycle just as the going gets rough in the first few weeks of April.
Late spring perennials are more trustworthy than annuals too, with far fewer boom or bust cycles. Spring annuals are prone to throw uncontrollable temper tantrums by sometimes never germinating at all or scaring everyone by holding their breath and not germinating until January like they did this year. Blessed with a more mature persona, late spring perennial plants have less to prove. They’re perfectly willing to benefit from the same moisture and growing conditions that annuals enjoy, yet they’re willing to admit that they owe much of their physical fitness (good or bad) to the growing conditions of previous years. To be fair, even though annuals can be trying at times, their performance is held hostage by the whims of the current season’s weather.
Brittlebush, Encelia farinosa, is a bit smug because it is a crossover. It’s a perennial plant that can germinate and grow in great quantities like an annual, covering entire hillsides in a near monoculture of yel-low flowers in April, like it did in 2008 and 2010. And then, to leave no doubt as to its well-rounded char-acter, it hunkers down with the rest of the surrounding jojobas, chollas, creosotes, prickly pears, and palo verdes, and stays the course, bravely taking on the brutality of six months of summer. Its Achilles’ heel is its lack of frost tolerance, but it makes up for this trifling handicap with a fast spring recovery and a reputation as one of the Sonoran Desert’s most drought-resistant plants.
Over time, the perennial plants of the second half of spring have developed an attitude and who can blame them? They prove their beauty and unflagging resolve year after year, yet they’re underappreciated by the great proportion of year-round residents that quickly trade refrigeration for perspiration and seasonal residents that flee aridity for humidity. It’s quite possible that most long-time winter residents that have been coming to Arizona from Minnesota or Alberta for a dozen years may have never seen a cholla flower, or the velvety orange petal of a mariposa lily, or even the magnificent white flowers crowning Arizona’s most famous cactus. These gems and many others like them are reserved for the rest of us who don’t have the good sense to beat the heat.
Even with the best of intentions, life cycles progress quickly in the desert and it’s easy to miss the passage of flowering events without some measure of predictability. Who wants to wait until next year? Rules of thumb work to a degree, such as the fact that the flowers of foothill palo verdes always follow blue palo verdes, and ironwoods and saguaros usually flower about the same time in mid-May. Better still is a chart that summarizes flowering events over time.
This table has been updated as of January 2015 and includes both annuals and perennials during the entire spring and early summer wildflower season.