Bloom Reports from the Anza-Borrego Desert: 2019-2020

6 December 2019

19 December 2019
Fig. 1. Baby plants of Phacelia distans, common phacelia, in Borrego Palm Canyon on two different dates, 13 days apart. The babies germinated from the good 20 November 2019 rain, were producing their first baby true leaves on 6 December, and had a handful of full-size true leaves on 19 December. They won't start blooming until at least February 2020.
Click on the photos for larger versions.


It is going to be at least a decent flower year essentially throughout the Borrego Desert. As of 27 December 2019, we've had a good start to the rainfall season, with everyplace getting at least two full inches of rain at the best time of year, late November through December. The Borrego Springs area has gotten about three inches of rain so far, well above the average rainfall through the end of December in Borrego Springs of 1.8 inches. The rainfall in areas east of Borrego Springs is even more significantly above their average rainfall, since the November and December storms have been unusually widespread in the desert. For a complete summary of the rainfall so far by location, see Fred Melgert and Carla Hoegen's rainfall graph.

However, to have a good flower year, we need more rain in January and February 2020, like we had last season. And, unfortunately, Sahara mustard is making a comeback in many areas, and will choke out the wildflower bloom in those areas, such as roadsides along S22 east of Borrego Springs west of the Thimble Trail, and probably in the Borrego Dump area. See Sahara Mustard Reduction in Numbers in the Borrego Desert Floor in 2015 for how wonderful it was immediately after the drought years. Sahara mustard still hasn't made a full comeback in some good wildflower areas, such as in the desert sunflower field along Henderson Canyon Road, and the area north of the end of the pavement for Di Giorgio Road, probably because people have been weeding it out of those areas. Those areas should still be good for native wildflowers this year.

The best indication of the widespread rainfall so far is that the ocotillos are green everywhere along S22, from the lower part of the Montezuma Grade along S22 through the Borrego Badlands. Annual germination has been observed everywhere we've hiked since 30 November. Most of the germination so far is in shadier areas, such as areas shaded by canyon walls, wash edges, and under shrubs. Very little germination has been observed in open washes, but that is not unusual; those annuals are probably waiting for warmer weather before germinating. Unfortunately, in many areas, Sahara mustard is the most common germinating annual. Worse, it is the dominant roadside plant in the Culp Valley Area, with some plants that germinated from the late September rain already quite large.

The temperatures in the desert have been cool, which is exactly what we want for a good bloom, allowing the plants to grow larger before blooming. This means we will probably not have any widespread blooms until February 2020 at the earliest. The progress of the bloom will probably follow one of the lower curves in this plot.

Last year, we had excellent rain in a swath of areas on October 12 and 13, which produced good annual germination, which resulted in blooms beginning in December. That didn't happen this year. The late September rain was too early to germinate winter annuals on the desert floor, except in an extremely few isolated locations where water runoff was concentrated. The late September rain did germinate a lot of roadside annuals at higher elevations such as Culp Valley, mostly Sahara mustard.

Right now we are limping along with just five to 20 species in bloom on each hike, and generally with just a few plants of each species in bloom; see the reports and graph in Fred Melgert and Carla Hoegen's 2019-2020 bloom report. To see 20 species in bloom, you need to be in open areas with flowing water, such as Coyote Creek Second and Third Crossings, or in the few areas where a few annual plants germinated from the 26 September 2019 rainfall and are now blooming, such as in Coachwhip Canyon and the Truckhaven Rocks area. We were very surprised to only find eight species in bloom in Borrego Palm Canyon on 6 December 2019.

Along the Montezuma Grade, a small number of Encelia farinosa, brittlebush, plants are in full bloom, ones that responded to the late September rain. Some ocotillos are in bloom, along with some plants of desert lavender.

The best source now to look for places to hike that have flowers you might be interested in, is the crowd-sourced iNaturalist to pick places that have species that you are interested in. You can get almost daily updates on what is blooming, or not blooming, in the Anza-Borrego Desert, as well as where species were found. Click on "Filters" and select a date range to see the observations from that period. For example, here are all the observations on 1 December 2019 and later, which had 376 observations through 27 December 2019. Each observation gives the date and time of observation, and the latitude and longitude for each observation, which is plotted on a map for you so you can see where it was from.

If you find species at iNat that you are interested in seeing, you can search just for recent observations of those species, and go where you see the most observations. Here is an example from last year: if you had wanted to see ghostflowers in bloom in early March 2019, there were 43 observations posted between 20 February and 2 March 2019. Clicking on the "Map" tab shows there were six separate locations where observations have been posted.

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

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

iNaturalist observations in the Borrego Desert since 1 December 2019 (click on "Filters" to change the dates)

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 (link will be supplied when they create their page this year) 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)

Go to:

Copyright © 2008-2019 by Tom Chester, Fred Melgert, Carla Hoegen, Walt Fidler, Nancy Accola, Don Rideout, Kate Harper, and Birgit Knorr.
Commercial rights reserved. Permission is granted to reproduce any or all of this page for individual or non-profit institutional internal use as long as credit is given to us at this source:
Comments and feedback: Tom Chester
Updated 28 December 2019