California’s Mojave and Colorado deserts get sporadic rainfall even during the best of times. Winter and spring of 2013 was one of the driest, with very few desert annuals blooming in the spring. But then the summer monsoon brought a few huge rainstorms to the desert southwest, producing flash floods and washed out roads. July, August, and September were all wet months in the desert, and the fall seemed like a good time to visit some desert washes and see what summer annuals the summer rains had wrought.
The trip would also give me a chance to try out my new (refurbished) Nikon D600, and see what twice as many pixels might produce. Here is an image from my first night out near the Granite Mountains in the Mojave National Preserve, featuring one of the largest Mojave yuccas I’ve ever seen. It was at least 10 feet tall with a dozen heads.
In the morning, the eastern flank of the Granite Mountains warmed up with the sun. (I recently learned that this image will be on the cover of the Jan. 2014 issue of Fremontia, the journal of CNPS – California Native Plant Society.)
The yellow flowers in the foreground are cinchweed, Pectis papposa var. papposa, an annual that blooms only in the summer and fall after summer rains. The leaves have prominent oil glands and the plant is strongly aromatic. I was going to become very familiar with this cheery little plant, as it was blooming essentially everywhere I went, from Barstow to Blythe and beyond.
Another view of ubiquitous cinchweed… 
… and one of the abundant cinchweed eaters, the caterpillar of a Sphinx moth, Hyles lineata, munching on Mirabilis leaves… These “hornworm” caterpillars were so thick in places it was hard to avoid stepping on them, or running over them on the road. But I did (avoid them that is).
The Cottonwood Spring area of Joshua Tree National Park picked up over 4” of rain in the summer, close to their total for a year. Evidence of flooding was everywhere. Below is a photo I made just to show how prolific cinchweed was. Notice the recent water flow through the center of this mass of flowers.
This image is from near the Cottonwood Spring CG, with the lower Eagle Mountains at sunset.
One plant that caught my attention in Chemeheuvi Valley is desert unicorn plant, or devil’s claw, AKA Proboscidea althaeifolia. The tubular fruits dry and curl at the tips, producing “claws, ” aiding in dispersal of the seeds. I was not familiar with it, but learned it is uncommon, and flowers only with good summer rains.
Chemehuevi Wash showed evidence of recent flooding with branches caught against the trunk of this blue palo verde tree (Parkinsonia floridus).
Desert willow (Chilopsis linearis arcuata) were also in bloom in Milpitas Wash, possibly for the second time this year since they typically flower from May to June. To its left is a dead smoke tree (Psorothamus spinosus), and in the back is blue palo verde.
With moonless nights, the Milky Way was clearly visible to the southwest after sunset. This is from Milpitas Wash, adjacent to the Palo Verde Mountains Wilderness, one of my favorite places in the Lower Colorado Desert. After turning off on Milpitas Wash Road, I did not see anyone for 24 hours when I got close to I-10 east of Desert Center. A fall trip to our deserts is a great way to spend a few days – no crowds, tolerable heat, and lots of flowers and butterflies if it has been a wet summer….
