Indeed, they say flowering plants are few and scattered in the south of Joshua Tree. Somewhat warmer temperatures during the last two weeks have produced lots of green leaves but it will take another couple of weeks for them to grow stalks, bud, and bloom, the park reports.
Here's the park's report:
A number of Joshua trees are beginning to bloom in the higher elevations. Bladderpod, which can be seen growing along the road from the North Entrance to Cottonwood, chuperosa along the road near Cottonwood, and ocotillo in Pinto Basin continue to provide the main color. Naturalist Bill Truesdell advises that the best way to see flowers this time of year is to stop when you see one, get out of your car, and walk around. That way you are likely to find others.
The extent and timing of spring wildflower blooms in Joshua Tree National Park may vary from one year to the next. Fall and winter precipitation and spring temperatures are key environmental factors affecting the spring blooming period. Normally desert annuals germinate between September and December. Many need a good soaking rain to get started.
In addition to rains at the right time, plants also require warm-enough temperatures before flower stalks will be produced. Green-leaf rosettes may cover the ground in January; however, flower stalks wait until temperatures rise.
Wildflowers may begin blooming in the lower elevations of the Pinto Basin and along the park’s south boundary in February and at higher elevations in March and April. Desert regions above 5,000 feet may have plants blooming as late as June.