Plant Species of the Borrego Desert: 2008-2009 Blooms

Table of Contents

Rainfall This Season

Annual Germination, Growth and Blooms
     General Requirements for Annual Germination
     Summary of Annual Germination, Growth and Blooms in 2008-2009

     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

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


The Borrego Desert is the northern part of Anza-Borrego Desert State Park below an elevation of 3000 feet, named for the Borrego Valley and the town of Borrego Springs (map and expanded definition).

This page gives some information about the early progress of the 2008-2009 bloom, concentrating 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 this page is given at the bottom of this page.

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 in the Borrego Desert; it only records the species I've seen in bloom on my hikes 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 Borrego Desert, especially for whether a widespread annual bloom is shaping up or not.

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.

The locations for each hike are in the report on annual germination below; more information is given in Botanical Trail Reports in Chronological Order, which usually includes more information about the bloom on each trip.

I will probably only record the detailed information given in this page as long as the number of species in bloom is relatively few. Once many species are in bloom, it would be too much work to record them all. But at that point, most readers will no longer care how well the bloom is progressing, since there will be lots of bloom.

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.

The following table 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. Occasionally other stations are missing in that report; if so, totals are taken from the Rainfall Summary Map.

There is no weather station in the Borrego Badlands; the rainfall estimates are just guesses made from how wet the area appears on trips there. If a station didn't appear in the summary, I 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.

DateFallbrookSan FelipeAgua CalienteBorrego Palm CanyonBorrego SpringsBorrego Badlands
8 August 20080.00?????
4 November 20080.
27 November 20081.810.510.520.310.35~0.30
15 December 20082.400.980.150.750.47~0.4?
17 December 20081.610.872.131.141.54~1.5?
22 December 20080.510.
25 December 20080.510.
3 January 20090.
23 January 20090.
26 January 20090.
7 February 20091.650.910.080.240.310.31?
9 February 20090.630.90?0.370.72?
16 February 20090.55??0.240.58?
Total Since 1 October10.23~5.3?3.5?3.053.99~3.0?

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.

Summary of Annual Germination, Growth and Blooms in 2008-2009

In 2008-2009, we received widespread significant rain (two inches on 15-17 December 2008) just in the nick of time for a fairly widespread moderate germination of most, but not all, of the annual species in many places. Unfortunately, no further rain fell for 52 days, until 7 February 2009. As a result, most annuals are smaller than normal, and will produce fewer blooms than in good years. Fortunately, the inch of rain on 7-9 February 2009, and the half inch of rain on 16 February 2009, helped many plants produce more blooms, and it has turned out to be a decent bloom season after all. In fact, the small size of the non-native Asian mustard, Brassica tournefortii, plants is allowing the smaller native plants to produce a better show!

Some annuals are blooming prolifically in many locations. For example, spectacle-pod, Dithyrea californica, was in full bloom along many portions of Coyote Canyon Road on 11 February 2009. A total of 33 annual species have been observed in bloom as of 17 February 2009 (see detailed list). We are within a week or two of peak bloom.

Some shrub species have been in peak bloom for some time. Chuparosa, Justicia californica, has been in peak bloom since late December 2008. Bladderpod, Isomeris arborea, has been in peak bloom in Rockhouse Canyon below Hidden Spring since 15 January 2009. Desert-lavender, Hyptis emoryi, has been in peak bloom there since 28 January 2009. Desert apricot, Prunus fremontii, was in peak bloom in Culp Valley and Rockhouse Canyon on 1 February 2009. Wishbone plant, Mirabilis bigelovii, began blooming on 11 February 2009, and soon will be in full bloom.

Some annual species are almost totally absent this year. I've seen only three live plants TOTAL of chia, Salvia columbariae, compared to seeing literally thousands of dead plants from previous years. This species just didn't germinate in most areas this year.

Detailed Germination, Growth and Bloom Reports From Each Hike

Detailed reports from the last month are given here; for earlier reports, see Reports from 28 November 2008 to 28 January 2009.

These reports are just summaries of these conditions from each hike. Many of these hikes have much more complete botanical reports online with additional information; see Plant Trail Reports, San Diego County, 2009.

1/19/09: Palm Wash. Many annuals and perennials are present along S22 near the entrance to Palm Wash, which is very encouraging. None are showing buds yet.

The first annuals were observed in bloom today at one spot in Palm Wash, pathetically-small specimens of the non-native Asian mustard, Brassica tournefortii. It was not an encouraging sight. They were only a few inches high, and will produce only a few flowers per plant. They were next to dead plants from last year that produced hundreds of flowers per plant. If we do not get more rain soon, many of the other annuals will bloom similarly pathetically.

Many plants of desert holly, Atriplex hymenelytra, were in full bloom. Desert tobacco, Nicotiana obtusifolia, was just beginning to bloom. One beautiful specimen of Borrego milk-vetch, Astragalus lentiginosus var. borreganus, was beginning its bloom.

1/24/09: Butler Canyon. The annuals are popping! We came across the first blooms of common phacelia, Phacelia distans; small-flowered poppy, Eschscholzia minutiflora; and even the first FRUIT of curvenut combseed, Pectocarya recurvata.

There were buds and/or the beginning flower stalks on a number of annual species, as well as buds on perennials and shrubs like cheesebush, Hymenoclea salsola; and rambling milkweed, Sarcostemma hirtellum. Many annual species will have their first blooms within weeks.

Not coincidentally, insects were out as well. Butterflies were mobbing a desert-thorn, Lycium brevipes, in bloom at Clark Lake.

Michael Charters shows some of the annual bloom, which came from small plants with only a few blooms per plant.

1/28/09: Rockhouse Canyon. Bladderpod, Isomeris arborea continues to be in full bloom, now joined by desert-lavender, Hyptis emoryi. The bloom of punctate rabbitbrush, Chrysothamnus paniculatus is ending. Buds of wishbone plant, Mirabilis bigelovii, look like they will pop in a week or two.

Although the first bloom of redstem filaree, Erodium cicutarium, was observed, none of the other annuals are as advanced as those in Butler Canyon four days ago.

2/1/09: Rockhouse Canyon. The bloom is similar to that on 1/28/09, with the following three additional annuals now in bloom. There is only a single very small plant of everlasting nest-straw, Stylocline gnaphaloides, that germinated here this year, and it is now in bloom. The first plants of many of the following two non-native annuals, Mediterranean schismus, Schismus barbatus; and Asian mustard, Brassica tournefortii, have begun to bloom here.

One plant of Parish's viguiera, Viguiera parishii, is beginning its bloom. Buds of cheesebush, Hymenoclea salsola, are growing larger and may begin blooming in the next week or two. Small buds have appeared on one plant of beavertail cactus, Opuntia basilaris, and on one plant of brittlebush, Encelia farinosa.

Chuparosa, Justicia californica, is in full bloom in Clark Valley along the Rockhouse Canyon Road.

One plant of brittlebush, Encelia farinosa, is in full bloom along S22 near the bottom of the Montezuma grade, but most plants there are not yet showing buds.

2/5/09: Rockhouse Canyon. The annuals have popped into full bloom at several locations along Rockhouse Canyon Road west of Clark Lake! We spent about an hour photographing about ten annual species that had popped into bloom in the last four days. All the usual suspects were there, including spectacle-pod, Dithyrea californica (one even had its first fruit!); narrow-leaved cryptantha, Cryptantha angustifolia; brown-eyed primrose, Camissonia claviformis ssp. peirsonii; Spanish needle, Palafoxia arida; desert dandelion, Malacothrix glabrata, and hairy sand verbena, Abronia villosa. We found some perennial / subshrub plants of California fagonia, Fagonia laevis, in full bloom there as well. Chuparosa, Justicia californica, continues in full bloom along the Road.

On our car stops along Rockhouse Canyon Road, and hike up Rockhouse Canyon to upper Rockhouse Canyon, we saw over 500 individual specimens of 42 species in bloom. In Rockhouse Canyon, Bladderpod, Isomeris arborea; and desert-lavender, Hyptis emoryi; continue to be in full bloom. In the upper canyon, desert apricot, Prunus fremontii, is still in full bloom, but is near its end.

However, the annuals have not yet begun blooming in most locations here.

2/11/09: Coyote Canyon Road, Box Canyon. There are carpets of flowers now along Coyote Canyon Road, most of them from spectacle-pod, Dithyrea californica, which is in full bloom seemingly everywhere along the Road. Some plants have their first beautiful fruit that looks like spectacles. Dune primrose, Oenothera deltoides; hairy sand-verbena, Abronia villosa var. villosa; and brown-eyed primrose, Camissonia claviformis ssp. peirsonii; have all begun blooming in the area at the end of Di Giorgio Road.

Driving along Coyote Canyon Road reveals new species in bloom regularly, including the first blooms of desert dandelion, Malacothrix glabrata, in a number of places. There is no water at First Crossing, so many passenger cars, driven carefully, can make it to Second Crossing. We were pleased to find a nice patch of longbeak streptanthella, Streptanthella longirostris, between First and Second Crossing.

Most annuals in Box Canyon have not yet begun blooming.

On our car stops along Coyote Canyon Road, and hike up Box Canyon, we saw over 1100 individual specimens of 53 species in bloom!

2/17/09: Rockhouse Canyon Road, Henderson Canyon Road, Coyote Canyon Road, Box Canyon. The carpets of flowers along Coyote Canyon Road are even better, with desert dandelion, Malacothrix glabrata; Fremont pincushion, Chaenactis fremontii; and desert chicory, Rafinesquia neomexicana, beginning to join the show.

Hairy sand-verbena, Abronia villosa var. villosa, is now producing its usual carpets of flowers along S22. The first hairy desert-sunflower, Geraea canescens, blooms have appeared along Henderson Canyon Road.

Buds of desert lily, Hesperocallis undulata, will pop in about a week at S22 and Rockhouse Canyon Road.

On our car stops along Henderson Canyon and Coyote Canyon Roads, and hike up Box Canyon, we saw over 1600 individual specimens of 61 species in bloom!

Most annuals in Box Canyon are still the same, and have not yet begun blooming.

Pictures From Each Hike

Most 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; I link 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 given in the botanical reports from each hike.

In contrast, on those hikes where Michael Charters came along, he documented most of the plants in bloom, and placed them on standard webpages with common and scientific names. I recommend you click on his pages first.

November 28
December 4
December 9
December 12
December 19
December 23
December 29
January 2
January 7
January 12
January 15
January 19
January 24
January 28
February 1
February 5
February 11
February 17

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

The annual bloom has not reached peak yet, so no predictions can be made for how long it will last. Peak bloom will probably begin in late February 2009.

Species in Bloom On Each Trip

Number of Species and Plants in Bloom On Each Trip

Four plots are given below:

The plots and the table here must be interpreted cautiously, since long hikes will find more plants in bloom. For example, the hikes of 12/29, 1/2 and 1/9 were all in Henderson Canyon, but were 4, 7 and 8 miles long, respectively. The increase in the number of plants was due almost entirely to the length covered.

I've added two bars in each plot, that represent the time of peak bloom estimated by Park Rangers. Two bars were needed since I wasn't sure of the meaning of the word between in the Park Rangers statement that they anticipate the peak blooming season to hit between the 3rd week of February and the 2nd week of March, depending on the weather. The lower pink bar extends from the beginning of the third week of February (2/15) and the end of the second week of March (3/14). The upper green bar extends from the end of the third week of February (2/22) to the beginning of the second week of March (3/7).

Hikes in the same general area on successive trips are color-coded in the table headers below. If the color changes between columns, it is a tip-off that different environments, and hence plant species, might have been sampled. There is no significance to the color used; only the change in color is significant.

The following table gives the numbers used for the above plots, for the last two months. For earlier numbers, see Numbers from 28 November 2008 to 28 January 2009. The individual observations used to obtain these numbers are in the List of Species in Bloom On Each Trip.

Number of1/21/71/121/151/191/241/282/12/52/112/17

List of Species in Bloom On Each Trip

The table 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.

This table gives the number of plants in bloom only since 1 January 2009. Some species thus have no number of plants in bloom listed in this table since they were observed in bloom only on trips prior to that date. For those earlier trips, see list of species seen in bloom from 28 November 2008 through 28 January 2009.

#FAMScientific NameCommon Name1/21/71/121/151/191/241/282/12/52/112/17
1ACAJusticia californicachuparosa5050502 305079809999
2ASCAsclepias albicanswhite-stemmed milkweed    2      
3ASCAsclepias subulatarush milkweed   111     
4ASCSarcostemma hirtellumrambling milkweed          1
5ASTAmbrosia dumosaburroweed           
6ASTBaccharis salicifoliamule fat         2020
7ASTBebbia juncea var. asperasweetbush1  5073020103053
8ASTChaenactis fremontiiFremont pincushion         110
9ASTChrysothamnus paniculatuspunctate rabbitbrush   99  30101  
10ASTEncelia farinosabrittlebush         230
11ASTEncelia frutescensbutton encelia           
12ASTEricameria brachylepisboundary goldenbush121        
13ASTGeraea canescenshairy desert-sunflower          10
14ASTGnaphalium luteo-album*common cudweed          5
15ASTGutierrezia sarothraematchweed  1    1111
16ASTHymenoclea salsola var. salsolacheesebush        15050
17ASTIsocoma acradenia var. acradeniaalkali goldenbush    1      
18ASTLepidospartum squamatumscale-broom   20  21   
19ASTMalacothrix glabratadesert dandelion        12550
20ASTPalafoxia arida var. aridadesert needle      2254040
21ASTPeucephyllum schottiipygmy-cedar    3      
22ASTPleurocoronis plurisetaarrow-leaf         13
23ASTRafinesquia neomexicanadesert chicory         230
24ASTStephanomeria pauciflora var. pauciflorawire-lettuce2222       
25ASTStylocline gnaphaloideseverlasting nest-straw       1   
26ASTTrixis californica var. californicaCalifornia trixis        1  
27ASTViguiera parishiiParish's viguiera       1521
28ASTXylorhiza orcuttiiOrcutt's woody-aster           
29BORCryptantha angustifolianarrow-leaved cryptantha        54099
30BORCryptantha barbigerabearded cryptantha         11
31BORCryptantha micranthapurple-root cryptantha         5 
32BORCryptantha pterocaryawing-nut cryptantha          1
33BORPectocarya heterocarpachuckwalla pectocarya          2
34BORPectocarya recurvatacurvenut combseed     1    99
35BRABrassica tournefortii*Asian mustard    20  10209999
36BRADescurainia pinnatawestern tansy-mustard         10 
37BRADithyrea californicaspectacle-pod        209999
38BRAGuillenia lasiophyllaCalifornia mustard        1  
39BRALepidium lasiocarpum var. lasiocarpumhairy-podded pepper-grass         310
40BRASisymbrium irio*London rocket         3099
41BRAStreptanthella longirostrislongbeak streptanthella         2020
42CACMammillaria dioicaCalifornia fish-hook cactus      111103
43CAPIsomeris arboreabladderpod   99 29999991010
44CHEAtriplex hymenelytradesert holly    20      
45CHEChenopodium murale*nettle-leaved goosefoot         520
46EUPChamaesyce polycarpasmall-seeded spurge   5   1555
47EUPCroton californicusCalifornia croton          5
48EUPDitaxis lanceolatanarrowleaf ditaxis  22 32129950
49EUPEuphorbia erianthabeetle spurge         2 
50EUPStillingia linearifolialinear-leaved stillingia        211
51FABAstragalus lentiginosus var. borreganusBorrego milk-vetch    1      
52FABCercidium floridum ssp. floridumblue palo verde           
53FABLotus rigidusdesert lotus   1  151031
54FABLupinus arizonicusArizona lupine         1020
55FABMarina parryiParry's marina   1       
56FABPsorothamnus emoryiEmory's indigo-bush    11 1   
57FABPsorothamnus schottiiindigo bush         1 
58FOUFouquieria splendens ssp. splendensocotillo371010355112010
59GERErodium cicutarium*redstem filaree      1 59999
60HYDPhacelia distanscommon phacelia     3  109999
61KRAKrameria grayiwhite rhatany           
62LAMHyptis emoryidesert-lavender 1230 209999995050
63LAMSalvia eremostachyadesert sage      111  
64NYCAbronia villosa var. villosahairy sand-verbena        13099
65NYCAllionia incarnatatrailing four o'clock          1
66NYCMirabilis bigelovii var. retrorsawishbone plant         510
67ONACamissonia claviformis ssp. peirsoniibrown-eyed primrose        103099
68ONACamissonia pallida ssp. pallidapale sun-cup        111
69ONAOenothera deltoides ssp. deltoidesdune primrose         2020
70PAPEschscholzia minutiflora ssp. minutiflorasmall-flowered poppy     3  203030
71PAPEschscholzia parishiiParish's poppy        1230
72PLAPlantago ovatadesert plantain          5
73POLEriogonum deflexum var. deflexumflat-topped buckwheat           
74POLEriogonum inflatumdesert trumpet111 105  1 1
75POLEriogonum wrightii var. nodosumWright's buckwheat3030302  105122
76ROSPrunus fremontiidesert apricot 1      20  
77RUTThamnosma montanaturpentine broom   1 122 21
78SCRMimulus bigelovii var. bigeloviiBigelow's monkeyflower         5 
79SIMSimmondsia chinensisjojoba         22
80SOLDatura wrightiisacred datura         11
81SOLLycium andersoniiAnderson's desert-thorn     2  1 3
82SOLLycium brevipes var. brevipesdesert-thorn     10 1   
83SOLLycium fremontiiFremont box-thorn          5
84SOLNicotiana obtusifoliadesert tobacco    42 1 33
85SOLPhysalis crassifoliathick-leaved ground cherry     11 2 2
86VISPhoradendron californicumdesert mistletoe      1131 
87ZYGFagonia laevisCalifornia fagonia        3205
88ZYGLarrea tridentatacreosote bush   21 11223
89POAAristida purpureapurple three-awn        2  
90POACynodon dactylon*Bermuda grass      1    
91POAPennisetum setaceum*fountain grass   1  11222
92POAPleuraphis rigidabig galleta     3  1210
93POASchismus barbatus*Mediterranean schismus       11015

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

DesertUSA Anza-Borrego Desert State Park Wildflower Reports For 2009

Anza-Borrego Desert Wildflowers: Where and When to Look from the Anza-Borrego Desert Natural History Association

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

Anza-Borrego Foundation and Institute Wildflowers (link didn't work on 9 February 2009)

Theodore Payne Wildflower Hotline (Reports begin on 6 March 2009)

Carol Leigh's California Wildflower Hotsheet

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Copyright © 2008-2009 by Tom Chester.
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 me at this source:
Comments and feedback: Tom Chester
Updated 19 February 2009.