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?
Total Since 1 October9.684.292.88+?2.813.41~3.0?

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 will help many plants produce more blooms, and it looks to be a decent bloom season after all.

Some annuals are blooming prolifically in scattered 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 28 annual species have been observed in bloom as of 11 February 2009 (see detailed list). The Anza-Borrego Desert State Park rangers anticipate the peak blooming season to hit between the 3rd week of February and the 2nd week of March, depending on the weather. This estimate seems reasonable to me.

Some shrub species are already in peak bloom in some areas. 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.

Additional perennial and shrub plant species are coming into bloom regularly. Wishbone plant, Mirabilis bigelovii, began blooming on 11 February 2009, and soon will be in full bloom.

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.

1/12/09: Henderson Canyon. Conditions similar to 1/7/09, with the annuals still growing. Some Phacelia distans plants are getting quite large. Newly-germinated annuals, mostly Phacelia distans and Pholistoma membranaceum, are still appearing in a few moist shady spots! Rock crossosoma, Crossosoma bigelovii; and wishbone plant, Mirabilis bigelovii, now have buds.

1/12/09: Rockhouse Canyon. The portion of the canyon below Hidden Spring has hundreds of plants total of four species in bloom: bladderpod, Isomeris arborea; punctate rabbitbrush, Chrysothamnus paniculatus; sweetbush, Bebbia juncea; and desert-lavender, Hyptis emoryi. Bladderpod is in full bloom; desert lavender is beginning its bloom, and the other two species are ending their bloom. It won't be long before wishbone plant, Mirabilis bigelovii, joins them in bloom.

There is decent annual germination here, although some of the annuals looked like they could use some rain.

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!

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.

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.

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

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 first two plots show what was observed on each trip, the total number of species in bloom and the total number of plants in bloom. The total number of plants in bloom for each individual species is capped at a maximum of 99 plants. The next two plots give the cumulative total numbers from all trips so far this season, of all species seen in bloom and of all annual species that germinated this year and have begun blooming. Thus this does not count any annual species that survived from last year and is now blooming. These cumulative total numbers include the number of species on a given trip as well as those from all trips previous to that trip.

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 of1/21/71/121/151/191/241/282/12/52/11

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. 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 includes only observations since 1 January 2009. Some species have no number of plants in bloom 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 Name1/21/71/121/151/191/241/282/12/52/11
1ACAJusticia californicachuparosa5050502 3050798099
2ASCAsclepias albicanswhite-stemmed milkweed    2     
3ASCAsclepias subulatarush milkweed   111    
4ASTAmbrosia dumosaburroweed          
5ASTBaccharis salicifoliamule fat         20
6ASTBebbia juncea var. asperasweetbush1  507302010305
7ASTChaenactis fremontiiFremont pincushion         1
8ASTChrysothamnus paniculatuspunctate rabbitbrush   99  30101 
9ASTEncelia farinosabrittlebush         2
10ASTEncelia frutescensbutton encelia          
11ASTEricameria brachylepisboundary goldenbush121       
12ASTGutierrezia sarothraematchweed  1    111
13ASTHymenoclea salsola var. salsolacheesebush        150
14ASTIsocoma acradenia var. acradeniaalkali goldenbush    1     
15ASTLepidospartum squamatumscale-broom   20  21  
16ASTMalacothrix glabratadesert dandelion        125
17ASTPalafoxia arida var. aridadesert needle      22540
18ASTPeucephyllum schottiipygmy-cedar    3     
19ASTRafinesquia neomexicanadesert chicory         2
20ASTStephanomeria pauciflora var. pauciflorawire-lettuce2222      
21ASTStylocline gnaphaloideseverlasting nest-straw       1  
22ASTTrixis californica var. californicaCalifornia trixis        1 
23ASTViguiera parishiiParish's viguiera       152
24ASTXylorhiza orcuttiiOrcutt's woody-aster          
25BORCryptantha angustifolianarrow-leaved cryptantha        540
26BORCryptantha barbigerabearded cryptantha         1
27BORCryptantha micranthapurple-root cryptantha         5
28BORPectocarya recurvatacurvenut combseed     1    
29BRABrassica tournefortiiAsian mustard    20  102099
30BRADescurainia pinnatawestern tansy-mustard         10
31BRADithyrea californicaspectacle-pod        2099
32BRAGuillenia lasiophyllaCalifornia mustard        1 
33BRALepidium lasiocarpum var. lasiocarpumhairy-podded pepper-grass         3
34BRASisymbrium irioLondon rocket         30
35BRAStreptanthella longirostrislongbeak streptanthella         20
36CACMammillaria dioicaCalifornia fish-hook cactus      11110
37CAPIsomeris arboreabladderpod   99 299999910
38CHEAtriplex hymenelytradesert holly    20     
39CHEChenopodium muralenettle-leaved goosefoot         5
40EUPChamaesyce polycarpasmall-seeded spurge   5   155
41EUPDitaxis lanceolatanarrowleaf ditaxis  22 321299
42EUPEuphorbia erianthabeetle spurge         2
43EUPStillingia linearifolialinear-leaved stillingia        21
44FABAstragalus lentiginosus var. borreganusBorrego milk-vetch    1     
45FABCercidium floridum ssp. floridumblue palo verde          
46FABLotus rigidusdesert lotus   1  15103
47FABLupinus arizonicusArizona lupine         10
48FABMarina parryiParry's marina   1      
49FABPsorothamnus emoryiEmory's indigo-bush    11 1  
50FABPsorothamnus schottiiindigo bush         1
51FOUFouquieria splendens ssp. splendensocotillo3710103551120
52GERErodium cicutariumredstem filaree      1 599
53HYDPhacelia distanscommon phacelia     3  1099
54KRAKrameria grayiwhite rhatany          
55LAMHyptis emoryidesert-lavender 1230 2099999950
56LAMSalvia eremostachyadesert sage      111 
57NYCAbronia villosa var. villosahairy sand-verbena        130
58NYCMirabilis bigelovii var. retrorsawishbone plant         5
59ONACamissonia claviformis ssp. peirsoniibrown-eyed primrose        1030
60ONACamissonia pallida ssp. pallidapale sun-cup        11
61ONAOenothera deltoides ssp. deltoidesdune primrose         20
62PAPEschscholzia minutiflora ssp. minutiflorasmall-flowered poppy     3  2030
63PAPEschscholzia parishiiParish's poppy        12
64POLEriogonum deflexum var. deflexumflat-topped buckwheat          
65POLEriogonum inflatumdesert trumpet111 105  1 
66POLEriogonum wrightii var. nodosumWright's buckwheat3030302  10512
67ROSPrunus fremontiidesert apricot 1      20 
68RUTThamnosma montanaturpentine broom   1 122 2
69SCRMimulus bigelovii var. bigeloviiBigelow's monkeyflower         5
70SIMSimmondsia chinensisjojoba         2
71SOLDatura wrightiisacred datura         1
72SOLLycium andersoniiAnderson's desert-thorn     2  1 
73SOLLycium brevipes var. brevipesdesert-thorn     10 1  
74SOLNicotiana obtusifoliadesert tobacco    42 1 3
75SOLPhysalis crassifoliathick-leaved ground cherry     11 2 
76VISPhoradendron californicumdesert mistletoe      1131
77ZYGFagonia laevisCalifornia fagonia        320
78ZYGLarrea tridentatacreosote bush   21 1122
79POAAristida purpureapurple three-awn        2 
80POACynodon dactylonBermuda grass      1   
81POAPennisetum setaceumfountain grass   1  1121
82POAPleuraphis rigidabig galleta     3  12
83POASchismus barbatusMediterranean schismus       1101

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

Go to:

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 12 February 2009.