Wednesday, July 24, 2013


     In the middle of summer, when daytime temperatures are often 110 degrees, there is a palpable tension in this shimmering desert landscape, accentuated by the high-pitched trill of small cicadas that cling to the limbs of mesquite. When the sun is at its highest and shade is reduced to its least accessible form, only lizards and ants seem unaffected by the heat. Before the monsoon season empties its heavy clouds, the desert seems to go into hibernation. The plants are rooted in place, slightly shriveled, and must tolerate the sun as best they can. There are few blooms; you may find, beneath a canopy of spines, the small wilted pink flowers of chain-fruit cholla.  Most animals have adjusted their activities to night. All the living things await rain.
     If you look up “desert” in a dictionary, you will often find that besides describing an arid environment, there is a secondary definition of a place being “lifeless and dull” or a “wasteland.” I can’t help but be irritated by those who would equate the desert with a wasteland. I would argue that the desert is one of the least wasteful environments in the world.  Looking out over the desert, I see organisms that have successfully co-evolved to frugally use what limited resources are available. (I’m not including Homo sapiens as one of those frugal organisms. We are a fairly recent invasive species to the deserts of our western hemisphere. How long have people been in the deserts of the American southwest? Probably around 12,000 years. Coincidentally, humans arrived at the same time the mammoth and giant ground sloth disappeared. Or is that a coincidence? Our arrival signaled an accelerated disappearance of animals that had been surviving here for millennia.) 
     If I were to quickly describe a desert, I would say that it is an environment where evaporation exceeds precipitation. In other words, it is a land that incrementally loses water over a long period of time. Water is necessary for life to exist, of course, and a complex of life exists in the desert.
     Not all deserts are equal in their aridity. Here in the United States, our driest, hottest desert is the Mojave which includes well-known Death Valley. There you can find animals and plants specifically adapted for surviving severe desiccating conditions.  (Consider the kangaroo rat, which can live its entire life without drinking water. It gets the moisture it needs to survive from seeds it collects for food. It can also slow its metabolism to minimize moisture lost through respiration.)
     The Sonoran Desert, where you find Boyce Thompson Arboretum, is one of the wettest deserts in the world. But in this comparatively lush environment, we still plainly see that plants and animals conserve water. Cacti have a protective waxy cuticle. Small leaves of the jojoba and manzanita point upward to avoid direct sunlight. Legume trees have developed pinnate leaf structures for filtering light and creating soft shade. There isn’t a native organism here that doesn’t show evolutionary signs of regional adaptation.  It is for us to study and understand the nuances of these adaptations.  If we can’t understand them, at least we might be able to appreciate the intermingling patterns of past and present.
     At its hottest, with the sun beating down, the desert certainly seems inhospitable and alienating to humans. Only foolish people and naturalists will venture out into this country on a mid-July afternoon. But far from being a wasteland, the desert is a supremely refined biome that functions on a narrow margin. There is very little waste to be found in this environment except for the waste created by its human inhabitants. Think “Las Vegas.”

Wednesday, July 10, 2013

La Fleur Fatale

The row of red yuccas in black plastic pots had been in the same location for weeks. Hundreds of red flowers lined flexible stems that waved in shallow arcs or wide ones, depending on the wind, and I took casual notice of them just as I do of all the other plants in the retail nursery. Thickened, lance-shaped leaves grew from each of these pots and then arched outward, allowing room for meter-high flowering stalks to rise from the center. Because they were perched atop an elevated rock wall, the flowers were effectively at eye level, filling in the landscape behind them.   

It wasn’t until an errant stem brushed across my cheek that I realized what I had been missing.  The flowers weren’t just deeper red than most red yuccas, they were the color of blood, pulsating with bright arterial blood near the center, transitioning to a darker venous color at the tips. A sudden lustfulness rose up inside me, and with it, a primal urge to possess them all—at least as many as my credit card would bear.

On left, the common red yucca. On right, Brakelights.
Up to now, I was only aware of the common, often-overplanted species form of red yucca (Hesperaloe parviflora) that can easily reach 6-7 feet across with a daunting thicket of tightly packed leaves. And while it looks great in front of office buildings or along freeways, it is often too large and gangly for home landscapes. The plant that was now plucking my heartstrings is a trademarked cultivar of this species called Brakelights. It not only has much redder flowers, but a mature size of just a third of its parent. Petite, you might say, rather than full figured. It is exceptionally heat tolerant and cold hardy, too, down to minus 20 degrees, which means it can be grown anywhere in Arizona, from Yuma to Flagstaff. And because it produces few seeds, it can flower for nine months of the year, attracting hummingbirds all the while.   

The flower petals of the species form of red yucca are painted a delicate raspberry sherbet color outside and bone white inside, like each color was lithely applied with the clear strokes of a fine horsehair brush. Yellow-tipped stamens poke out through the floral tube, and, from a distance, the cumulative effect is a deep pinkish hue.  The flowers of Brakelights, however, are unapologetically blood-red through and through, as if dunked into a bowl of pomegranate syrup and hung to dry, dripping thick and heavy. Even the stamens have shrunk almost out of sight to help magnify the Big Red effect. In sun, the red flowers glow—like brake lights—and appear backlit even when they’re not; under clouds, the pigments remain untamed and intoxicating.  

I had already planted three of the regular red yuccas in my yard, long before I became enamored with the intense beauty and diminutive size of Brakelights. But plant fidelity is not one of my strong points (after all, there is no higher calling in landscape design than to choose the right plant for the right place, even if it takes several tries to get it right), so I unceremoniously dug out the original red yuccas and replaced them in the same location with Brakelights, preserving the older plants in the empty containers.

Is this a case of trading a reliable old standby for the seductive power of a new introduction? What some might call a trophy plant? Perhaps, but now, after several weeks of comparing the two plants side-by-side, I have a renewed appreciation for the subtle artistry of the common red yucca flowers when compared to the drunken allure of Brakelights. Even with its rambunctious vegetative growth, the common red yucca suggests that it sips from a glass, with stately elegance, while the upstart Brakelights brashly chugs from the bottle, not genteel enough to wipe its chin, but never outgrowing its location, either. 

For size, color, and length of flowering alone, Brakelights is a superior choice for most home yards and landscapes, but if space isn’t an issue, the common red yucca still has its charm. In the end, the choice will depend on how thirsty you are. 

Kim Stone