Plant Species of the Borrego Desert: 2009-2010 Blooms

California fish-hook cactus, Mammillaria dioica
desert apricot, Prunus fremontii

Both pictures taken on 24 January 2010 in Hellhole Canyon (one canyon south of Borrego Palm Canyon immediately west of Borrego Springs) by Mike Crouse.


Table of Contents

Introduction
Rainfall This Season

Annual Germination, Growth and Blooms
     General Requirements for Annual Germination
     Peak Bloom: What Does That Mean?
     Summary of Annual Germination, Growth and Blooms in 2009-2010

     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


Introduction

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 information about the 2009-2010 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 this page is given at the bottom of this page.

For the progress of last year's bloom, see 2008-2009 Blooms.

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 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 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.

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

Table 1. Rainfall Events Since 1 October 2009

DateFallbrookSan FelipeAgua CalienteBorrego Palm CanyonBorrego SpringsBorrego Badlands /
Ocotillo Wells
13 October 20090.070.000.000.000.000.00
28 November 20090.420.200.080.140.030.00
7 December 20091.931.411.09~1.01.24~1.2
11-13 December 20091.460.5??0.3??0.130.18~0.00
22 December 20090.130.2?0.2?~0.080.08~0.00
18-22 January 20105.24~6.0?~6.0?~5.5?4.891.65
 
Total Since 1 October9.49~8.3?~7.7?~6.8?6.42~2.85

The reported rainfall of 0.34 inches for Borrego Palm Canyon on 12/7/09 is unlikely to be correct, since nearly everywhere in San Diego County received an inch of rain or more. Automatic rainfall gauges often get clogged, causing under-reported rainfall, which is probably what happened here. I've replaced it by an estimated 1.0 inches.

The rainfall given at the Visitor Center since July 1, 2009 matched closely the Borrego Springs total rainfall given above as of 12/31/09 since there was no monsoonal rain at the Visitor Center in 2009.

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.

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 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 2009-2010

The widespread inch of rain on 12/7/09 produced excellent native annual germination west of Borrego Springs, but as of mid-January 2010 poor native annual germination east of Borrego Springs. East of Borrego Springs, including the floor of eastern Clark Valley and Beckman Wash in the Borrego Badlands, almost 100% of the germinated annuals are the non-native Asian mustard, Brassica tournefortii.

The widespread 1.5-5 inches of rain on 18-22 January 2010 essentially guarantees a good wildflower display west of Borrego Springs unless we get several weeks of temperatures over 90° F. It remains to be seen whether this rainfall arrived early enough to produce good annual germination east of Borrego Springs. Even if native annuals were germinated from this rain, in many places they might be overwhelmed by the non-native Asian mustard due to its huge head start.

Detailed Germination, Growth and Bloom Reports From Each Hike

Detailed reports since 1 December 2009 are given here; for earlier reports, see Reports from 29 October 2009 to 24 January 2010.

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

See also Detailed Germination, Growth and Bloom Reports From Each Hike in 2008-2009.

12/1/09: Split Mountain Road south of Ocotillo Wells, Elephant Tree Area. The Split Mountain Road area south of Ocotillo Wells is simply amazing; it is green and full of flowers! The creosote bushes are dense with beautiful dark green foliage, and there are still carpets of chinch-weed, Pectis papposa, as far as the eye can see in places, all from a single thunderstorm on 9/5/09. Although most of the Pectis has finished blooming, there are still many plants that look beautiful, in full bloom.

Farther south, in the alluvial fan below Alma Canyon in the Elephant Tree area, we found a total of 59 species along our route, and an amazing 36 of them, 61%, had at least one plant in bloom, and typically many more. See the list in the table below. Some of the species that were not in bloom had fruit, like the elephant trees and Acacia greggii.

Altogether on this trip, we saw over 1,072 plants of 38 species in bloom. Not bad for early December!

12/5/09: Collins Valley, Cougar Canyon. The fabulous bloom of black-banded rabbitbrush, Chrysothamnus paniculatus, at the mouth of Indian Canyon has begun to fade, although there are still a number of plants in full bloom. Cougar Canyon has good displays of California fuchsia, Epilobium canum.

12/9/09: Split Mountain Road south of Ocotillo Wells, Elephant Tree Area, Alma Canyon. The bloom in this area continues to be perhaps the best in the Park, and the recent rainfall should rejuvenate the bloom for some species in the future. We saw over 675 plants of 36 species in bloom, including six species not seen on any previous trip so far this year.

12/15/09: Elephant Tree Area, Alma Canyon. The good bloom here continues, with some species rejuvenated by the recent rain. For example, the Allionia blooms are much better now than they were six days ago.

Amazingly, one perennial plant, Lyrocarpa coulteri var. palmeri, Coulter's lyrepod, is already producing blooms on a plant just a few inches high just eight days after the rain. This plant must have already emerged and grew to its present size prior to the rain, since when we saw the plant on 12/27/09, 20 days after the rain, it looked virtually the same.

We saw over 660 plants of 29 species in bloom.

12/19/09: Clark Valley. We saw only 34 plants of 7 species in bloom today, which is more typical of most places in the Borrego Desert than the places we have been visiting so far this season. It is too early for blooms in most places that don't have a permanent source of water, or received summer rainfall.

We saw a zillion baby annuals that have sprouted, but unfortunately they are all silver dollar size clumps of the non-native Asian mustard, Brassica tournefortii. It is hard to imagine that just 15 years ago this invasive species was not even present here.

12/23/09: Agua Caliente County Park. This area is not in the Borrego Desert, but its report is included here anyway. The star of the show for me was seeing a single open bloom of Lycium parishii, Parish's desert-thorn, which is found only south of the Borrego Desert. This was the first time I had seen this species in bloom. We saw 18 species total in bloom. (Since this area is not in the Borrego Desert, the numbers from this trip are not included in the plots and tables below, or in the list of species in bloom.)

12/27/09: Elephant Tree Area, Alma Canyon, Starfish Cove. The bloom was almost identical to what was seen on 12/15/09, but we noticed fewer plants of each species in bloom, since this was mostly a hiking trip so we could finally get to Starfish Cove.

12/31/09: California Riding and Hiking Trail, Lower Hellhole Canyon part. It seemed like we had gone back in time by coming to this area after the Elephant Tree Area. Annuals were just germinating, with many showing just their cotyledons or first true leaves. Some of the shrubs were just leafing out.

1/3/10: California Riding and Hiking Trail, Culp Valley and upper Hellhole Canyon part. This trip was at 2600 feet elevation and above, and very few plants were in bloom. Interestingly, some of the annuals were a bit more advanced than seen lower on this trail four days ago, instead of being a bit farther behind.

1/7/10: Hellhole Canyon to Maidenhair Falls. There is excellent annual germination in Hellhole Canyon itself, and decent germination underneath the shrubs on the alluvial plain below. In particular, the Phacelia distans plants are growing robustly, with ~8 good-sized leaves or so on each plant. About ten plants of bladderpod, Isomeris arborea, are in good bloom.

1/10/10: Borrego Badlands: Fonts Point Wash and Beckman Wash. It was almost shocking to see the lack of native annual germination in this area. To a first approximation, the only annuals that have germinated here are those of the non-native Asian mustard, Brassica tournefortii. We only observed a few baby plants of narrow-leaved cryptantha, Cryptantha angustifolia, and a few other native annuals. Worse, even if native annuals germinate later, they will be overwhelmed by the non-native Asian mustard due to its huge head start.

We observed rosettes of 3-4 leaves on several desert lilies, Hesperocallis undulata, but the last leaf reverted to a much-smaller size, indicating that it might be running of our moisture. That doesn't augur well for its good bloom unless we get further rain.

As is often the case, the number of plants in bloom in the Borrego Badlands was way less here than we observed any place else so far this year. We found a grand total of 4 plants in bloom, each a different species.

We also found a single plant on the S22 roadside of Salton milk-vetch, Astragalus crotalariae, with a number of buds.

1/15/10: Hellhole Canyon to beyond Maidenhair Falls. Conditions are much the same as on 1/7/10, with the annuals all a bit bigger.

1/24/10: Hellhole Canyon to beyond Maidenhair Falls. It rained! It rained a lot! This hike was delayed by six days due to a glorious five days of rain.

Hellhole Canyon Creek is flowing quite strongly above the Canyon mouth; water is shooting down Maidenhair Falls; the ground is wet everywhere; and the annuals are looking great. The annuals are no longer little rosettes with a few leaves in many places; they are now forming masses with foliage some distance above the ground.

The widespread ~5 inches of rain here on 18-22 January guarantees a good wildflower display to come at least in this canyon.

The stars of the show today were a few specimens of California fish-hook cactus, Mammillaria dioica, in full bloom along the portion of the trail in the alluvial fan, and the first few plants of desert apricot, Prunus fremontii in bloom (both pix by Mike Crouse).

We observed three tiny plants of the first winter annual in bloom, but unfortunately the species was the non-native redstem filaree, Erodium cicutarium.

Pictures From Each Hike

Most of the pictures in the Pictorial Gallery of Species in Bloom To Date in 2009-2010, organized by flower color, have been taken this year. 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

20092010
October 29
November 15
November 19
November 22
November 25
December 1
December 5
December 9
December 15
December 19
December 23
December 27
December 31
January 3
January 7
January 10
January 24

See also Pictures From Each Hike in 2008-2009.

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

No predictions can be made, since most of the annuals are still germinating and/or growing.

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

Figure 2. Number of Plants in Bloom on Each Trip

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

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

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

Table 3 gives the numbers used for the above plots, for the last two months. For earlier numbers, see Numbers from 29 October 2009 to 24 January 2010. 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 of12/112/512/912/1512/1912/2712/311/31/71/101/151/24
Species391936297251051141014
Plants1073459675660342696761004149151

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.

This table gives the number of plants in bloom only since 1 December 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 29 October 2009 to 24 January 2010..

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 except the following:

This table gives the number of plants in bloom only since 1 December 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 29 October 2009 to 24 January 2010.

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 Name12/112/512/912/1512/1912/2712/311/31/71/101/151/24
1ACAJusticia californicachuparosa30505099 2030 50 9999
2AMAAmaranthus fimbriatusfringed amaranth10 11        
3ASCAsclepias subulatarush milkweed            
4ASCSarcostemma cynanchoides ssp. hartwegiiclimbing milkweed            
5ASTAdenophyllum porophylloidesSan Felipe dogweed1  1      1 
6ASTAmbrosia dumosaburroweed1           
7ASTAmbrosia psilostachyawestern ragweed            
8ASTBaccharis salicifoliamule fat 5      2   
9ASTBebbia juncea var. asperasweetbush9929999550215 52
10ASTBrickellia desertorumdesert brickellia            
11ASTChrysothamnus paniculatuspunctate rabbitbrush19955        
12ASTConyza canadensishorseweed            
13ASTDicoria canescensdesert dicoria            
14ASTEncelia farinosabrittlebush5 510 2      
15ASTEricameria brachylepisboundary goldenbush 1    21    
16ASTGutierrezia sarothraematchweed 1051        
17ASTIsocoma acradenia var. eremophilasolitary-leaved alkali goldenbush            
18ASTLepidospartum squamatumscale-broom            
19ASTPalafoxia arida var. aridadesert needle99155     1  
20ASTPectis papposa var. papposachinch-weed99 10         
21ASTPerityle emoryiEmory's rock-daisy111  1      
22ASTSenecio flaccidus var. monoensisMono ragwort            
23ASTSolidago californicagoldenrod           1
24ASTStephanomeria exigua ssp. exiguaslender wreathplant            
25ASTStephanomeria pauciflora var. pauciflorawire-lettuce50140151102 3   
26ASTViguiera parishiiParish's viguiera       1    
27BORCryptantha angustifolianarrow-leaved cryptantha1           
28BORCryptantha racemosabushy cryptantha 5203 1      
29BORHeliotropium curassavicumseaside heliotrope            
30BORTiquilia palmeriPalmer's coldenia1           
31BORTiquilia plicataplicate coldenia            
32BRABrassica tournefortii*Asian mustard  1         
33BRALyrocarpa coulteri var. palmeriCoulter's lyrepod  13 1      
34CACMammillaria dioicaCalifornia fish-hook cactus        1  3
35CAPIsomeris arboreabladderpod        10 1010
36CHEChenopodium murale*nettle-leaved goosefoot  2         
37EUPChamaesyce micromeraSonoran spurge5 110        
38EUPChamaesyce polycarpasmall-seeded spurge99105020 1020     
39EUPChamaesyce setilobaYuma spurge99 9999 10      
40EUPCroton californicusCalifornia croton115       1  
41EUPDitaxis lanceolatanarrowleaf ditaxis99 5020 5      
42EUPDitaxis neomexicanaNew Mexico ditaxis      1     
43EUPEuphorbia erianthabeetle spurge1 31        
44FABAcacia greggiicatclaw   1        
45FABLotus rigidusdesert lotus  11   1    
46FABProsopis glandulosa var. torreyanahoney mesquite            
47FABPsorothamnus emoryiEmory's indigo-bush 15  2    1  
48FABPsorothamnus schottiiindigo bush10 101011  1 11
49FOUFouquieria splendens ssp. splendensocotillo79959920205 1512020
50GERErodium cicutarium*redstem filaree           3
51GRORibes indecorumwhite-flowering currant           1
52KRAKrameria grayiwhite rhatany10 10         
53LAMHyptis emoryidesert-lavender99 99993992 5 105
54LOAPetalonyx thurberi ssp. thurberiThurber's sandpaper-plant            
55MALHibiscus denudatusrock hibiscus1           
56MALHorsfordia newberryiNewberry's velvet mallow3           
57MALMalacothamnus aboriginumIndian Valley bush mallow        5 11
58NYCAbronia villosa var. villosahairy sand-verbena1 2         
59NYCAllionia incarnatatrailing four o'clock99 2030 20      
60NYCBoerhavia intermediafivewing spiderling10           
61NYCBoerhavia wrightiiWright's spiderling30           
62NYCMirabilis bigelovii var. retrorsawishbone plant1 12 1      
63ONACamissonia cardiophylla ssp. cardiophyllaheartleaf sun-cup 55  1      
64ONAEpilobium canum ssp. latifoliummountain California-fuchsia 10          
65ONAEpilobium ciliatum ssp. ciliatumwillowherb            
66ONAOenothera elata ssp. hirsutissimaHooker's evening-primrose            
67PLAPlatanus racemosawestern sycamore            
68POLEriogonum elongatum var. elongatumlong-stemmed buckwheat 99          
69POLEriogonum fasciculatum var. polifoliumCalifornia buckwheat2    1      
70POLEriogonum inflatumdesert trumpet2011010231 3   
71POLEriogonum wrightii var. nodosumWright's buckwheat 30   22   11
72ROSPrunus fremontiidesert apricot           3
73SCRMimulus cardinalisscarlet monkeyflower            
74SOLDatura discolordesert thornapple50 50  1      
75SOLDatura wrightiisacred datura            
76SOLLycium andersoniiAnderson's desert-thorn            
77SOLNicotiana obtusifoliadesert tobacco  11 1      
78SOLPhysalis crassifoliathick-leaved ground cherry3 410 6      
79SOLSolanum douglasiiwhite nightshade            
80VISPhoradendron californicumdesert mistletoe       2    
81ZYGFagonia pachyacanthasticky fagonia3 2         
82ZYGLarrea tridentatacreosote bush5 1         
83LILAgave desertidesert agave     1    11
84POAAristida adscensionissix-weeks three-awn5 53 1      
85POABouteloua aristidoides var. aristidoidesneedle grama10  1 1      
86POABouteloua barbata var. barbatasix-weeks grama  11        
87POAPleuraphis rigidabig galleta2           

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

DesertUSA Anza-Borrego Desert State Park Wildflower Reports For 2010

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 in March 2010)

Carol Leigh's California Wildflower Hotsheet


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Copyright © 2008-2010 by Tom Chester.
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Comments and feedback: Tom Chester
Updated 25 January 2010.