By Louise Bustard
April and May in the Southwestern states of America is cactus flowering time. It is a time of plenty for all; for the creatures which feed on the vast reservoirs of nectar provided by a cactus flower; and for the flowers which are visited and hopefully pollinated by myriad insects, bees, bats, moths and birds. It is spring and the chill winter is past. Surprisingly, winter in both the Sonoran and Mojave Deserts can be extremely cold. The temperatures regularly drop well below freezing resulting in frequent frosts and occasional snow falls. Even in late May day-time temperatures in the high desert regions can be uncomfortably low as I discovered whilst travelling through the Joshua Tree National Monument in Southern California. As I stood by a Joshua Tree (Yucca brevifolia) trying to photograph it, I felt a little foolish with my blue shorts, blue legs and fingers too cold to press the shutter.
The desert proved to be a land of endless surprises. I had expected to find a bare and barren wilderness but what actually confronted me was a landscape bursting with countless varieties of life forms. As one of the more recent (geologically speaking) climatic environments to appear on Earth, both the flora and fauna now inhabiting desert areas have evolved the ability to endure the extreme nature of the desert. Many of the adaptations to withstand extremes of temperature and intense aridity followed by flash floods are unique and in many cases extremely bizarre. The structure of a cactus with ribs to permit shrinkage in dry periods and swelling during the rains also to create some shade on their neighbours; a waxy cuticle to prevent excessive water loss; spines to create more shade and to form a layer behind which cool air is trapped during the heat of the day and warm air during the cool nights, all these features lead one to believe that mother nature works it all out logically.
I was surprised by the obvious difference between two neighbouring desert states, California and Arizona. In Arizona both the people and their laws actively support the conservation of their desert and their wildlife. Unlike many of their Californian neighbours they do not shun their native plants. The gardens, parks and municipal buildings are generously landscaped using the native flora. Some exotics are used of course, Palms, Jacarandas, Oleandas and various South African and Australian trees line the streets. The laws limiting the use of water in Arizona restricts the use of plants to drought-tolerant species and looks perfectly in harmony with the desert environment.
Each state through which the Colorado River flows is permitted to take a specified amount of its water. Arizona’s forward-looking approach to conservation of water and energy production means that it only removes two thirds of its allotted quota.
California on the other hand takes its full quota and the third which Arizona leaves behind. I found the wasteful use of water in California quite shocking. Here the residents, whilst revelling in the sunshine and clean air (at least, those not living within 50 miles of Los Angeles) of the desert, seem very reluctant to use their native flora and prefer to surround themselves with plants more at home in the rainforest. To maintain this effect of a green and pleasant land garden irrigation systems were kept running for almost the entire day and the streets in many of the suburban areas I visited were literally running with water.
If I had to choose just one highlight from my desert travels, helped by a Kew Guild Award Scheme grant, it must be the four days I spent camping in the Sonoran Desert in northern Mexico. Two marvellous people, desert-lovers and plant growers from Tuscan took me into the rarely visited depths of the desert looking westward towards the Gulf of California and the peninsula of Baja. With a combined bottomless pit of knowledge about the desert and all that exists within it, Chuck Hanson and Meg Quinn taught me to love this extraordinary place and consequently develop a greater understanding of my plants and their needs.
On our final night in Mexico we sat by the camp fire in complete silence until darkness fell. There was a full moon in a sky so full of stars they looked like sequins on a black velvet dress. The canyon in which we were camped occasionally echoed to the sound of an owl or a badger screeching. The moon was the brightest I had ever seen as its light cascaded down upon the desert scene creating a magical effect. In the distance the seas in the Gulf of California (Sea of Cortes to the Mexicans), shone like a pool of silver, silhouetted against this were the huge 15ft tall Pachycereus pringlei columnar cacti.
Suddenly we heard a noise from above. The night creatures were about. We got up and walked down the canyon, no torches were used, our world was alight with gleaming silver and blue. As we wove our way past the shrubs some of their strange shapes appeared more unworldly than ever. The inflated base and spindly limbs of the elephant bush Bursera microphylla suddenly became a dollop of ice cream with broken wafers stuck in it. The baffling ‘Boojum’ Idria columnaris took on the appearance of a giant carrot ejecting itself from out of the ground. We came to a halt at the base of a huge ‘Cardon’ (Pachycereus pringlei). Its large white flowers (almost two inches across) only open after dark when they emit a sweet odour. As Chuck shone his powerful torch up to the tops of these magnificent giants the answer to why their exquisite flowers only show themselves at night became clear. There, with its head buried deep within a flower was a bat. These extraordinary mammals feed on the nectar offered by the flower. In return they pollinate with their heads which are completely covered in bright yellow pollen from the massive numbers of anthers which have to be penetrated before the nectar can be reached.
That night as I lay in my sleeping bag I reflected on how much I had learned in the desert, that it is a place full of life and not the barren emptiness we often believe it to be. “Perhaps”, I thought, “I won’t try too hard to change peoples’ negative view of the desert, then, with luck it may remain unvisited and unspoilt”. “On the other hand”, I said to myself, “Just think what they’ll be missing”.