Bloom Reports from the Anza-Borrego Desert: 2021-2022

Table of Contents

Latest Summary of Bloom Status
Bloom Reports from Individual Hikes This Season
Links to Other Webpages on Anza-Borrego Desert State Park Blooms
Background Information for Bloom Reports from the Anza-Borrego Desert
Older Bloom Reports from 2009 to present

Fig. 1. Left: Proboscidea althaeifolia, desert unicorn plant. Right: Senna covesii, desert senna. Click on the pix to get views of entire plants.

Both pix by Jim Roberts. The linked pix of the Proboscidea is also by Jim Roberts. The linked pix of the Senna is by Nancy Accola. All pix were taken on 19 August 2021.

Latest Summary of Bloom Status

Summary as of 20 August 2021

Monsoonal thunderstorms producing enough rain to germinate summer annuals occurred in scattered locations of parts of the Borrego Desert in late July and early August 2021. These scattered locations are generally places where water ponded during the rains, and are surrounded by areas that have few or no summer annual plants.

On 19 August 2021, we surveyed a route along SR76, SR79, and S2 from the Lake Henshaw area to Vallecito Station County Park, stopping where we saw patches of green from recent plant growth, or where we saw flowers. We saw over 1,000 plants in bloom of at least 40 species; see the list using scientific names, or the list using common names.

Fred Melgert reports that Ferocactus cylindraceus and Cylindropuntia ganderi have been posted in bloom on Facebook.

Fig. 1 shows two of the showiest species we found in bloom, Proboscidea althaeifolia, desert unicorn plant; and Senna covesii, desert senna.

Unfortunately, biting bugs, perhaps "no-see-ums" since the bugs themselves were not obvious, were also present in most of these locations, as well as some annoying bugs in places that had to be hand-waved away repeatedly. Tom received at least nine bites that produced angry red bumps the next day, mostly in areas under my t-shirt and shorts. Nancy reported a similar number of bites, despite wearing long sleeves and long pants. These bugs almost always accompany monsoonal annuals in bloom in our area.

We also observed a large area where essentially all the ocotillos had leafed out. See Fig. 2.


Fig. 2. Locations surveyed on 19 August 2021 (red dots). Locations with abundant monsoonal plants are circled in red. The area where nearly every ocotillo had fully leafed out is outlined in green. The single location where desert unicorn plants were observed is labeled.

What was surprising is that the location with the highest reported rain total, 2.5 inches at Scissors Crossing on 10 August 2021, had zero annual germination! There was evidence of significant recent water flow there, so it is a mystery why no summer annuals germinated there so far. Also, four locations within the area where all the ocotillos had leafed out also had very poor annual germination.

Bloom Reports from Individual Hikes This Season

The latest bloom reports are given first (i.e., the reports are in inverse order of time).

19 August 2021. See above.

Links to Other Webpages on Anza-Borrego Desert State Park Blooms

Anza-Borrego Wildflowers Bloom Report by Fred Melgert and Carla Hoegen, often with daily wildflower updates.

All iNaturalist observations in the Borrego Desert since 1 August 2021 (click on "Filters" to change the dates; there were 67 observations of 36 species post as of 21 August 2021.)

Wildflower Updates from the Anza-Borrego Desert Natural History Association.

Anza-Borrego Desert State Park official site, with wildflower information on it. When they start producing current wildflower reports, click on the link near the top with the word Update, which might be updated weekly.

DesertUSA Anza-Borrego Desert State Park Wildflower Reports

Anza-Borrego Foundation and Institute Wildflowers and their Anza-Borrego Desert State Park Wildflower Hotline: (760)767-4684. "Information on this recording is updated regularly."

Theodore Payne Wildflower Hotline (Reports begin the first Friday in March)

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Copyright © 2008-2021 by Tom Chester, Nancy Accola, Jim Roberts, and Birgit Knorr.
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Updated 22 August 2021