Bloom Reports from the Anza-Borrego Desert: 2015-2016

Fig. 1. Left: the first blooming plant of Geraea canescens, hairy desert-sunflower, in the sunflower field area just north of Henderson Canyon Road. The linked picture also shows how much smaller the plants of Eulobus californicus (=Camissonia californica) are in 2016 compared to the stalk from 2015.
Right: A Hesperocallis undulata, desert lily, with four blooming stalks, from about one mile north of the end of the pavement on Di Giorgio Road.
Photographs taken on 26 February 2016. Click on the pictures for larger versions.

See also Pictures shown here on prior dates.

See Bloom Reports from the Anza-Borrego Desert for an introduction to this page, extensive general information (not specific to this year) about Annual Germination, Growth and Blooms, including what influences the duration and extent of the annual bloom, photo galleries, and links to other webpages giving information on Anza-Borrego Desert State Park Blooms.

Summary of Blooms in 2015-2016

The annual bloom on the desert floor, and of shrubs along S22 on the Montezuma Grade, is a month later than normal, and has just begun to take off in the last week of February 2016 (but see note about a few spots with plants that began blooming in January 2016). The number of plants and species in bloom on 26 February 2016 is the lowest we've recorded in the last eight years, but that is primarily because of the month delay in the start of the bloom; we expect that the peak bloom will be that of a fairly typical year. Although most of the annual plants on the desert floor are significantly smaller than what would be seen in a good year, that is not unusual for an average year. And as is often the case, the perennials and shrubs look happy with the rainfall they got, even though it was below normal.

So far, this year appears to match the 2012-2013 bloom year in the number of species in bloom on an average trip. The plot of the number of species in bloom vs. time for the last eight years for this year (solid black line) is following closely the turquoise line for the 2012-2013 season. 2012-2013 was a decent bloom year, but somewhat subpar compared to other years. This year is better than 2012-2013 in having many more annuals in bloom on the desert floor.

The wonderful news about the lack of Sahara Mustard, Brassica tournefortii, continues! For the second year in a row, the mustard is not the dominant plant on the sandy desert floor in most places, allowing us to see our native plants blooming there (See Sahara Mustard Reduction in Numbers in the Borrego Desert Floor in 2015).

The bloom should continue getting better over the next few weeks. And as is often the case, some species have responded well to the unique rainfall pattern of each year. For example, desert lilies, Hesperocallis undulata, are having an excellent year, with abundant blooms (see photograph at top of this page).

We expected a much better and more widespread bloom this year from all the super-El Niño hype, and the predictions of two inches of rain in the desert in October 2015 that never materialized. Unfortunately, this year has been yet another below-normal rainfall in the Borrego Desert. There was only a single rainfall event in the Borrego Desert, of two inches in and west of Borrego Springs on 5-6 January 2016, and of just an inch or less east of Borrego Springs. This produced good, but somewhat spotty, germination in and west of Borrego Springs, but only very scattered germination east of Borrego Springs.

There was only one small rainfall event after that, on 31 January 2016, of just 0.04 to 0.4 inches in Borrego Springs, and nothing east of there.

Conditions were almost the exact opposite of what it takes to produce a good bloom. The germinating rainfall was late, followed by a month of temperatures ten degrees colder than normal that produced almost no growth for the annuals. Then the weather suddenly turned hot, with temperatures ten degrees warmer than normal. The lack of further rain, and the warm temperatures, caused the annual plants to begin blooming when they were very small. For example, the desert sunflower, Geraea canescens, are starting to bloom when they are just one foot tall or less, about half their usual size (see Fig. 1). These smaller plants will produce many fewer blooms than normal-size plants would.

Fig. 2 shows photographs of the sunflower field area just north of Henderson Canyon Road on 2 March 2009, with a good bloom of Geraea canescens but seriously compromised by abundant Brassica tournefortii, with roughly the same view on 26 February 2016, within five days of the same time of year. The good news in 2016 is that Brassica tournefortii is still nearly absent. The bad news in 2016 is the very much smaller size of the Geraea canescens plants.

Fig. 2. Top: View of the sunflower field area just north of Henderson Canyon Road on 2 March 2009. Bottom: A similar view on 26 February 2016. More of the foreground is shown for the 26 February 2016 view to show the relative sparseness of the plant cover then.

See List of species observed in bloom on 26 February 2016 from a drive down Montezuma Grade (beginning at 3000 feet elevation in Culp Valley), and from three locations on the desert floor northeast of Borrego Springs.

Note about a few spots with plants that began blooming in January 2016

A few areas just south of the eastern Santa Rosa Mountains, such as the Truckhaven Rocks area, received some significant rain in September and/or October 2015. That caused spotty germination in that area, especially in locations where water pooled, and produced scattered plants that were huge and blooming in January 2016. That included the largest plants of Plantago ovata, Cryptantha maritima, and C. barbigera fergusoniae we've ever seen.

Predictions for This Year

Peak bloom will probably occur in mid-March or so. Without further rainfall and cooler temperatures, the period of peak bloom will probably be shorter than normal.

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Updated 2 March 2016