Bloom Reports from the Anza-Borrego Desert: 2010-2011

Bigelow's monkeyflower, Mimulus bigelovii
Photograph of field of Mimulus bigelovii
glandular nemacladus, Nemacladus glanduliferus
Photograph of Nemacladus glanduliferus

Pictures of two annual plants taken on 19 January 2011 in Harper Canyon. The Mimulus plant is about the size of your hand; the Nemacladus flower is only a few mm (0.1 inch) across (note the pen tip for scale)

Recent updates to this page:

Table of Contents

Rainfall This Season

Annual Germination, Growth and Blooms
     General Requirements for Annual Germination
     Bad Bloom Years Are All The Same; Good Bloom Years Are All Different
     Peak Bloom: What Does That Mean?
     Summary of Annual Germination, Growth and Blooms in 2010-2011

     Detailed Germination, Growth and Bloom Reports From Each Hike
     Pictures From Each Hike

How Long Will An Annual Bloom Last
     General Factors
     Predictions for This Year

Species in Bloom On Each Trip
     Number of Species and Plants in Bloom On Each Trip
     List of Species in Bloom On Each Trip, With Photographs
     Pictorial Gallery of Species in Bloom To Date in 2009-2010, organized by flower color

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


I've expanded the scope of this bloom report page in 2010-2011 to include a larger area of the Anza-Borrego Desert State Park and nearby areas, since I plan on botanizing a larger desert area this season than I have in years past. Pages for 2008-2009 and 2009-2010 were restricted to the Borrego Desert portion of the Park.

In all cases, these pages only give the bloom status below 3000 feet elevation. Most observations are typically at about 1000 feet elevation.

This page gives information about the 2010-2011 bloom for all species in this area, with emphasis on the annuals that are responsible for the widespread showy blooms that appear in some years on the desert floor. The date of the last update to the text of this page is given at the bottom of this page. However, the plots below showing the progress of the bloom are always kept up to date, even if this page hasn't been recently updated otherwise.

The plots below also show the progress of the bloom in 2008-2009 and 2009-2010. For detailed progress of the bloom in those years, see 2009-2010 Blooms and the links therein.

In addition to specific information about current conditions, this page also gives some general information on what is needed to germinate those annuals, and what is needed to sustain the annual bloom.

The information here is by no means a definitive list to what is blooming at all locations in the Anza-Borrego Desert; it only records the species I've seen in bloom on my trips that occur roughly every fourth day. Because the locations change, the numbers of species in bloom, and the number of plants in bloom, cannot usually be directly compared from trip to trip. However, the information here will give the reader an idea of what the bloom is doing in the Anza-Borrego Desert.

Note that there is often quite a difference in the annual bloom between the moister canyons west of Borrego Springs and the drier areas around the Badlands. Similarly, even within those canyons on the west, there can be large differences between the north-facing and south-facing slopes, and between canyons with permanent water, like Borrego Palm Canyon, and drier canyons. In the drier areas to the east, there can be large differences between the edges of washes and the middle of washes, and between shady canyons and open areas. Location matters!

The locations for each hike are in the detailed reports below; sometimes more information is given in Botanical Trail Reports in Chronological Order, which usually include more information about the bloom on each trip.

Rainfall This Season

Rainfall is the most important determinant of blooms. Rainfall is usually highest on the mountain slopes, especially on the west edge of the Borrego Desert, and falls off dramatically with lower elevation to the east. This occurs whenever our rainfall is mostly orographic. However, when rainfall is from convection, the deserts can at times get more rainfall than the coast. (See Precipitation types.)

In addition to desert stations, I've also given the rainfall from my house in Fallbrook, on the coastal side at 680 feet elevation, to show the large difference in rainfall between the wet side of the mountains and the dry side.

Table 1 gives the storm totals, in inches, as of the last day of each storm. The storm totals were taken from the Weather Service Rainfall Storm Summary, except for Fallbrook and the Borrego Badlands / Ocotillo Wells. Occasionally other stations are missing in that report; if so, totals are taken from the Rainfall Summary Map. Rainfall reports for Ocotillo Wells are reported at here for the month to date.

If a station didn't appear in the summary, or I couldn't find it elsewhere on line, I usually assumed the rainfall total was zero. Although this assumption is probably usually correct, it is not necessarily always valid since missing data plague all rain reports. In a few cases, when it was clear that some rainfall must have been received at those missing stations, I've guesstimated the rainfall.

Note that the total rainfall at the bottom of the table is since 1 October, since rain that falls earlier doesn't germinate the desert annuals (see below). This rainfall total may be different from the rainfall reported by the Anza-Borrego Desert State Park Visitor Center using the normal California rainfall year that begins on 1 July. Also, the total rainfall also contains rainfall in Fallbrook not reported in the table if there was no major rainfall in the desert.

Table 1. Major Rainfall Events in the Desert Since 1 October 2010

End DateFallbrookSan FelipeAgua CalienteBorrego Palm CanyonBorrego SpringsOcotillo Wells
Total All Rain16.803.232.334.653.522.01

On 11/24/10, the Visitor Center billboard reported 2.44 inches of rain, compared to the total above of 1.57 inches from the National Weather Service station in Borrego Springs. This may be due to differences in rainfall between stations, or due to rainfall prior to 10/1/10.

Annual Germination, Growth and Blooms

General Requirements for Annual Germination

The timing of rainfall is extremely important for the annual bloom. Rainfall received in the summer and early fall will not germinate the annuals that bloom in February and March. Rainfall received after January will either not germinate those annuals, or will germinate them too late for them to produce a robust bloom in most years. Thus rain must fall in October, November, and/or December in order to germinate the annuals that produce the showy mass displays.

The amount in a single storm is also important. Native annuals require about an inch of rainfall, received over no longer than a period of something like several days, in order to germinate. Our native annuals have learned the hard way that any less rainfall doesn't guarantee enough moisture in the soil for them to produce seeds.

Unfortunately, non-native annuals can germinate on less rainfall, and can sometimes get a head start over our native annuals if we get a first rainfall much less than an inch.

See Predicting Desert Wildflower Blooms - The science behind the spectacle from the Arizona-Sonora Desert Museum for information relating to Arizona desert blooms. Many of our annual species respond a bit differently, since we have much less monsoonal rain and more winter rain, but some of our species follow the Arizona rules.

Bad Bloom Years Are All The Same; Good Bloom Years Are All Different

Janice Emily Bowers, with her vast experience in desert blooms, said it best in her book Flowers and Shrubs of the Mojave Desert, 1998, p. 4:

... maybe one in five [springs] will bring a good wildflower display. All bad springs are more or less alike in that wildflowers are scarce or not to be seen, but all good years are different in that no two have the same abundance of flowers or the same combinations of species. This is because different kinds of annual wildflowers have different requirements for germination and growth.

This is just as true for the Borrego and Sonoran Deserts.

Peak Bloom: What Does That Mean?

The term Peak Bloom means different things to different people:

Most of the time, I use the latter definition of Peak Bloom, but I also try to mention when the carpets of flowers are present.

If you are looking for a particular species in bloom, the time of Peak Bloom doesn't matter to you; you want to know only when that species is in bloom. Plant species bloom at different times; it is not possible to see every species in bloom even over the time period of a month.

For example, if you want to see the beautiful blooms of beavertail cactus, Opuntia basilaris, you'll need to come just after the showy annual carpets are finished. If you want to see the beautiful flowers of desert-willow, Chilopsis linearis ssp. arcuata, then you'll need to come here in summer, when few species are blooming except for it.

See observed dates of peak bloom in 2008-2009 and in 2009-2010 for various locations.

These annual species produce the showy carpets of flowers:

Other annuals can produce carpets of flowers, but are either more limited in their distribution, such as Bigelow's monkeyflower, Mimulus bigelovii, or purple mat, Nama demissum; or don't produce such showy displays, such as Fremont pincushion, Chaenactis fremontii (since fields of white don't show up well against the whitish background of the desert soil).

Summary of Annual Germination, Growth and Blooms in 2010-2011

The widespread rainfall of 1-2 inches in the desert in mid-October 2010 woke up many perennials and shrubs, and began the annual germination.

Interestingly, the October rain germinated both summer annuals such as fivewing spiderling, Boerhavia intermedia; and chinch-weed, Pectis papposa; and winter annuals such as hairy sand verbena, Abronia villosa, all of which are blooming together now in an unusual juxtaposition.

As of 15 January 2011, on each single day trip we are consistently finding over 1,000 individuals in bloom of at least 40 species. Every trip reveals new species that have just come into bloom, and shows buds on other species that haven't yet bloomed.

The plots below show a consistent upward trend in both the total number of all species, and the total number of annual species, seen in bloom so far. Those plots show that we are now about halfway toward the numbers seen at the time of peak bloom.

In particular, as of 15 January 2011, we have seen 110 different species in bloom this season, out of a typical total of ~200-250 species seen by the end of the desert season.

The plots show that the bloom state this year is about one month earlier than last year.

Detailed Germination, Growth and Bloom Reports From Each Hike

These reports are just summaries of these conditions from each hike.

See also Detailed Germination, Growth and Bloom Reports From Each Hike in 2009-2010.

(Reports not added yet)

Pictures From Each Hike

See Photo Gallery of Desert Species Observed in Bloom for photographs organized by flower color. The date and location of each picture are given in that table.

Most of the rest of my pictures were taken for scientific purposes, and not specifically to show anything about the bloom. However, they may be of interest to people showing some aspects of what the bloom was like on a given date. My pictures are not even on standard webpages; Table 2 gives links to a directory and you have to click on the link for each picture to see it. Scientific names are used almost exclusively for the picture names.

The context for most of these pictures is sometimes given in the botanical reports from each hike.

Table 2. Links to Directories With Pictures From Each Trip

November 11
November 24
November 27
December 3
December 13
December 17

See also Pictures From Each Hike in 2009-2010.

How Long Will An Annual Bloom Last

General Factors

Past Rainfall, Future Rainfall, and Heat are the main factors determining how long an annual bloom will last on the desert floor at about 1000 feet elevation:

Predictions for This Year

This is going to be a good bloom year everywhere in the desert due to the two widespread heavy rain events.

If the trends seen in the plots below continue, we'll begin full bloom in early February, and probably get in at least a month of full bloom, and maybe more, before it gets too hot, frying the annuals. Many have been the March's where the bloom was suddenly ended by a spell of hot weather.

Of course, it is too early to tell whether we'll hit a plateau that delays full bloom to the same time as last year. But so far there is no evidence of such a plateau.

Species in Bloom On Each Trip

Number of Species and Plants in Bloom On Each Trip

Five plots are given below; each plot has this year's bloom data as well as last year's bloom data for comparison:

The plots and the table here must be interpreted cautiously, for at least three reasons:

Figure 1. Number of Species in Bloom on Each Trip

Graph showing the number of species found in bloom on each trip for 2008-2009 and 2009-2010

Figure 2. Number of Plants in Bloom on Each Trip

Graph showing the number of individual plants found in bloom on each trip for 2008-2009 and 2009-2010

Figure 3. Cumulative Number of Species Seen in Bloom From All Trips

Graph showing the cumulative number of species found in bloom for trips in 2008-2009 and 2009-2010

Figure 4. Cumulative Number of Annual Species Seen in Bloom From All Trips

Graph showing the cumulative number of annual species found in bloom for trips in 2008-2009 and 2009-2010

Figure 5. Percent of All Species Seen in Bloom From All Trips That Are Annuals

Graph showing the percent of all species cumulatively seen in bloom that are annuals for 2008-2009 and 2009-2010

Table 3 gives the numbers used for the above plots, for the last two months. The individual observations used to obtain these numbers are in the List of Species in Bloom On Each Trip.

Table 3. Number of Species and Total Number of Plants in Bloom on Each Trip

Number of11/1111/2411/2712/312/1312/17

List of Species in Bloom On Each Trip, With Photographs

Table 4 gives the number of plants observed to be in bloom for each species on each hike, with a maximum value of 99 plants for each species. This maximum value prevents one species from dominating the total plants in bloom, and makes it much easier on me to keep track of the bloom.

Because the hike locations vary, some species will not be present on every hike, so the lack of an entry for a given hike says nothing about whether that species is blooming elsewhere.

The Checklist is sorted first by category, with dicots before monocots, and then by family and scientific name. The Family and Scientific Name are from the Jepson Manual. An asterisk before the Common Name indicates a non-native taxon.

See Plant Family Abbreviations to obtain the full family name from the abbreviations used in the table below.

The Checklist has thumbnail photographs for most of the species, all of which were taken in the Borrego Desert. Clicking on the thumbnail photograph gives a larger version equal in size to the ones at the top of this page.

All the larger versions are also presented in Pictorial Gallery of Species in Bloom To Date in 2009-2010, organized by flower color.

All pictures were taken by myself, with a Sony Point and Shoot T9 camera except the following:

This table gives the number of plants in bloom only in the last two months.

Some species that have bloomed in the Borrego Desert are not listed here, since I never observed them in bloom. Such species are found only in a few locations, and I either never visited those locations or they bloomed in between my visits to their location.

Of course, species that bloom later in the year, and species that do not have flowers (ferns, etc.) are not present in this list, so it is not the equivalent of a plant checklist for the Borrego Desert.

Table 4. List of Species in Bloom On Each Trip

#FAMScientific NamePixCommon Name11/1111/2411/2712/312/1312/17
1ACAJusticia californicaPhotograph of flower of Justicia californicachuparosa  50  50
2AMAAmaranthus albusPhotograph of flower of Amaranthus albus*tumble pigweed     1
3AMAAmaranthus palmeriPhotograph of flower of Amaranthus palmeriPalmer's amaranth     1
4ASCAsclepias subulataPhotograph of flower of Asclepias subulatarush milkweed     5
5ASCMatelea parvifoliaPhotograph of flower of Matelea parvifoliaspearleaf   1  
6ASTAdenophyllum porophylloidesPhotograph of flower of Adenophyllum porophylloidesSan Felipe dogweed    1 
7ASTAmbrosia dumosaPhotograph of flower of Ambrosia dumosaburroweed 1    
8ASTBebbia juncea var. asperaPhotograph of flower of Bebbia juncea var. asperasweetbush 111525
9ASTChrysothamnus paniculatusPhotograph of flower of Chrysothamnus paniculatuspunctate rabbitbrush50  10  
10ASTDicoria canescensPhotograph of flower of Dicoria canescensdesert dicoria 10    
11ASTEncelia farinosaPhotograph of flower of Encelia farinosabrittlebush     5
12ASTEncelia frutescensPhotograph of flower of Encelia frutescensbutton encelia51   5
13ASTEricameria brachylepisPhotograph of flower of Ericameria brachylepisboundary goldenbush   9930 
14ASTGutierrezia sarothraePhotograph of flower of Gutierrezia sarothraematchweed   30251
15ASTHymenoclea salsola var. salsolaPhotograph of flower of Hymenoclea salsola var. salsolacheesebush  2   
16ASTIsocoma acradenia var. acradeniaPhotograph of flower of Isocoma acradenia var. acradeniaalkali goldenbush99     
17ASTMalacothrix glabrataPhotograph of flower of Malacothrix glabratadesert dandelion     1
18ASTPalafoxia arida var. aridaPhotograph of flower of Palafoxia arida var. aridadesert needle55    
19ASTPectis papposa var. papposaPhotograph of flower of Pectis papposa var. papposachinch-weed 9950   
20ASTStephanomeria pauciflora var. paucifloraPhotograph of flower of Stephanomeria pauciflora var. pauciflorawire-lettuce55210 1
21ASTTrichoptilium incisumPhotograph of flower of Trichoptilium incisumyellow-head     1
22ASTTrixis californica var. californicaPhotograph of flower of Trixis californica var. californicaCalifornia trixis     1
23ASTViguiera parishiiPhotograph of flower of Viguiera parishiiParish's viguiera 53 2020
24BIGChilopsis linearis ssp. arcuataPhotograph of flower of Chilopsis linearis ssp. arcuatadesert-willow10     
25BORCryptantha angustifoliaPhotograph of flower of Cryptantha angustifolianarrow-leaved cryptantha     10
26BRABrassica tournefortiiPhotograph of flower of Brassica tournefortii*Asian mustard     2
27BRALyrocarpa coulteri var. palmeriPhotograph of flower of Lyrocarpa coulteri var. palmeriCoulter's lyrepod   1  
28CACFerocactus cylindraceusPhotograph of flower of Ferocactus cylindraceusCalifornia barrel cactus  1   
29CARAchyronychia cooperiPhotograph of flower of Achyronychia cooperifrost mat     1
30EUPChamaesyce micromeraPhotograph of flower of Chamaesyce micromeraSonoran spurge 1    
31EUPChamaesyce polycarpaPhotograph of flower of Chamaesyce polycarpasmall-seeded spurge 599   
32EUPCroton californicusPhotograph of flower of Croton californicusCalifornia croton 5    
33EUPDitaxis lanceolataPhotograph of flower of Ditaxis lanceolatanarrowleaf ditaxis 250520 
34FABAstragalus crotalariaePhotograph of flower of Astragalus crotalariaeSalton milk-vetch1     
35FABHoffmannseggia glaucaPhotograph of flower of Hoffmannseggia glaucahog potato   2  
36FABLotus scoparius var. brevialatusPhotograph of flower of Lotus scoparius var. brevialatusshort-winged deerweed    30 
37FABPsorothamnus emoryiPhotograph of flower of Psorothamnus emoryiEmory's indigo-bush 5    
38FABPsorothamnus schottiiPhotograph of flower of Psorothamnus schottiiindigo bush 1    
39FOUFouquieria splendens ssp. splendensPhotograph of flower of Fouquieria splendens ssp. splendensocotillo 5   20
40GERErodium cicutariumPhotograph of flower of Erodium cicutarium*redstem filaree    1 
41KRAKrameria grayiPhotograph of flower of Krameria grayiwhite rhatany  1   
42LAMHyptis emoryiPhotograph of flower of Hyptis emoryidesert-lavender 25  15
43MALHibiscus denudatusPhotograph of flower of Hibiscus denudatusrock hibiscus 510  10
44NYCAbronia villosa var. villosaPhotograph of flower of Abronia villosa var. villosahairy sand-verbena 50    
45NYCAllionia incarnataPhotograph of flower of Allionia incarnatatrailing four o'clock 350 3 
46NYCBoerhavia intermediaPhotograph of flower of Boerhavia intermediafivewing spiderling  5   
47NYCMirabilis bigelovii var. retrorsaPhotograph of flower of Mirabilis bigelovii var. retrorsawishbone plant  201030 
48ONACamissonia californicaPhotograph of flower of Camissonia californicaCalifornia suncup     1
49ONACamissonia pallida ssp. pallidaPhotograph of flower of Camissonia pallida ssp. pallidapale sun-cup     1
50POLEriogonum deflexum var. deflexumPhotograph of flower of Eriogonum deflexum var. deflexumflat-topped buckwheat15     
51POLEriogonum fasciculatum var. polifoliumPhotograph of flower of Eriogonum fasciculatum var. polifoliumCalifornia buckwheat   1  
52POLEriogonum inflatumPhotograph of flower of Eriogonum inflatumdesert trumpet521030205
53POLEriogonum molestumPhotograph of flower of Eriogonum molestumpineland buckwheat    10 
54POLEriogonum wrightii var. nodosumPhotograph of flower of Eriogonum wrightii var. nodosumWright's buckwheat   992 
55RUTThamnosma montanaPhotograph of flower of Thamnosma montanaturpentine broom   5  
56SOLLycium andersoniiPhotograph of flower of Lycium andersoniiAnderson's desert-thorn   1  
57SOLNicotiana obtusifoliaPhotograph of flower of Nicotiana obtusifoliadesert tobacco    2 
58SOLPhysalis crassifoliaPhotograph of flower of Physalis crassifoliathick-leaved ground cherry    2 
59ZYGFagonia laevisPhotograph of flower of Fagonia laevisCalifornia fagonia  101  
60ZYGLarrea tridentataPhotograph of flower of Larrea tridentatacreosote bush  2  30
61ZYGTribulus terrestrisPhotograph of flower of Tribulus terrestris*puncture-vine 1   5
62POABouteloua barbata var. barbataPhotograph of flower of Bouteloua barbata var. barbatasix-weeks grama 1    
63POAPleuraphis rigidaPhotograph of flower of Pleuraphis rigidabig galleta 1011 1

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

Anza-Borrego Desert Wildflowers: Where and When to Look and latest report (usually from Bill Sullivan) from the Anza-Borrego Desert Natural History Association.

Anza-Borrego Desert State Park official site, with wildflower information on it. Click on the link near the bottom for the Flower Update and Map, which might be updated weekly.

DesertUSA Anza-Borrego Desert State Park Wildflower Reports For 2010

Carol Leigh's California Wildflower Hotsheet

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 on 5 March 2010)

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Copyright © 2008-2011 by Tom Chester.
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Updated 17 January 2011.