The assignment seemed simple enough: write an article forecasting the possibilities for this year's desert wildflower bloom, and incorporate "El Nino" as a contributing element. Weather, of course, is the single most important factor effecting the spring bloom, and in a typical (non-Nino) desert year, making a prediction is relatively simple.
Look up the rainfall for the last three months -- usually not much; dig a hole and measure how deep the soil moisture penetrates -- usually less than an inch; walk outside, lick your finger and count how many seconds it takes to dry -- usually not many. Wrinkle your forehead as if in deep thought, then write: If it doesn't rain pretty soon, there won't be much of a bloom this year."
I have watched the weather in Anza-Borrego Desert State Park for the past 25 years, and in most of those years the procedure I described above would have gotten me an accurate forecast. But this year is different -- really different! In September, a wonderful storm brought nearly two inches of gentle, soaking rain to the desert. While September rain is certainly not rare, two inches of gentle, penetrating rain is nearly un-heard-of in that month. Combined with the balmy temperatures which followed the storm, the rain caused millions of dormant seeds to germinate about four months earlier than usual. By the last week in November, the bloom which had developed was beyond anyone's wildest dreams. Never in my 25 years as a naturalist in Anza-Borrego has there been a fall bloom with either the variety or volume of flowers which appeared.
A number of important questions arose after the November bloom. How long would it last? Would the plants just go on growing and blooming, even though the temperatures were dropping and the days were becoming very short? Or, could they go dormant, and just wait out the cold, short days of winter, then "resurrect" with the return of warm weather? Or, could new seeds from these early bloomers be dropped to create the raw material for a second bloom in spring? How much time and drying and heat does a new seed need before it is mature enough to germinate? These are all questions that I (and all my "old-timer" friends) were unable to answer, for the simple reason that we had not seen this particular set of circumstances before.
Small rainstorms have continued to visit the desert since November (is this the work of El Nino?), and as of mid-January (when this article was written) precipitation was approaching four inches and soil moisture was a least eight inches deep. The spectacular bloom of Sand Verbena which developed in November has continued to spread, and in addition many other plants have begun to produce flowers, weeks earlier than usual. Among the plants which were showing at least a few early flowers by mid-January were: Desert Sunflower, Indigo Bush, Brown-eyed Primrose, Dune Evening Primrose, Desert Aster, Ocotillo, Rock Hibiscus and the closely related desert Mallow, Brittlebush, and even a few Smoketrees.
In answer to one of the most important questions asked above, nearly all of the plants which germinated in November have stayed alive. Some became dormant (like Desert Lilies), while quite a few others have continued to grow. The result is a substantial crop of rather large annual plants which, for the most part, are without flowers. Some of these plants are as big as I've ever seen in any previous spring -- they just seem to be waiting. What they are waiting for is not far off.
If I were to ignore the current crop of flowers, and simply look at the precipitation which has fallen since last September, I would say we could expect a better-than-average bloom. If the weather service folks are even close on their predictions of additional El Nino rainfall, I would be around the desert, at the enormous numbers of large annual plants which are found in almost every conceivable location, and combine that with the current depth of soil moisture, I would go out on a limb and say that we are about to see what could be The Mother of all Springs. As the days continue to lengthen, and temperatures rise, I believe all of those nearly-full-grown plants will soon explode into massive bloom. How soon? I think the main bloom will begin by mid-February.
So where does El Nino fit into all this? Some scientists feel that our "El Nino" for this weather season actually was at its peak back in the period of August and September of last year. That would account for the wonderful soaking rain we got during the fall. Whether they were brought by "El Nino" or not, a continuing string of winter storms has blown over the mountains, brining a nearly perfect pattern of soft, soaking rains. However, if one looks at the precipitation records, this weather year is not particularly wet -- San Diego is "average" for the season, so far, as is Anza-Borrego. What really sets this weather year apart from previous ones is the timing of the rains. If El Nino gets fired up again, and brings more rain in the near future, it can only enlarge and extend the bloom.
So, keep your fingers crossed, buy lots of film, invite all your friends and relatives because maybe we are about to see one of the blooms of the century. At any rate, I feel confident in suggesting that Spring will be early this year, and from the looks of it, VERY BIG.
-- Text and photos copyright Paul R. Johnson, (February 1998)
