Navajo Spinach (Cleome Serrulata): Improving Seed Germination from Wild Populations Gathered across Native Lands of the Four Corners

Final report for GW17-060

Project Type: Graduate Student
Funds awarded in 2017: $24,969.00
Projected End Date: 07/31/2018
Grant Recipient: Utah State University
Region: Western
State: Utah
Graduate Student:
Principal Investigator:
Dr. Daniel Drost
Utah State University
Expand All

Project Information


Native plants were commonly gathered and used by the Tribes of the Four Corners. One such plant is the Rocky Mountain Bee Plant, Cleome serrulata. This plant has several common names: stinkweed, stinking clover, skunk weed, and Navajo Spinach. Navajo Spinach is called “naá” by the Navajo, “túmi” by the Hopi, and “a’pilalu or ado:we” by the Zuni.  Historically, Navajo Spinach was a leafy vegetable in spring, plant tissue or seeds were used to color wool or paint pottery and baskets, and collected seeds were also ground for bread or eaten raw.

Navajo Spinach commonly grows on open rangelands, in disturbed soils around cultivated fields, and in sandy alluvial washes along stream beds. Wild populations of C. serrulata are scattered throughout the Four Corners. In 2016, we searched for wild populations of Cloeme from which we intended to collect seeds from for our germination studies. We also grew out seedlings from prior seed collection trips to increase seed stocks for additional study. 

Project Objectives:

1.  Collect Navajo Spinach from unique locations across the Navajo, Hopi and Zuni reservations.

Spinach seeds from Chinle, Arizona and Zuni, New Mexico were compared to commercially available seeds purchased from Great Basin Seed Company. Trips were taken to the Shonto, Chinle, and Keams Canyon areas of Northern Arizona and Southern Utah looking for additional Cleome populations. Dry weather conditions in 2016 had two effects on wild Cleome populations. First, while plants were found, wild plant population numbers were very low and quite scattered. Second, because of the hot, dry summer conditions, while plants flowered, pod set and pod seed numbers were very low. We did ID several new locations of plants and additional visits will be made to these sites in 2017 to collect seeds.

2.   Determine germination and growth requirements of Navajo Spinach seeds

Earlier studies show that germination is highest when seeds are chilled at 4C, less well at 10C and generally did not germinate at 20C. In January of 2017, we are repeating this experiment with a couple of changes. Treatments will include a 7C temperature (4, 7, 10, 20C). We will also double chill which will include exposing seeds to the various temperatures, returning them to room temperature, then placing them back into their respective cold temperatures for additional time. We are also evaluating various hormone treatments (GA 4, GA7 and GA4+7) along with the cold treatments. These are currently underway and data is just beginning to be collected. These studies will be repeated later in the spring.

3. Explore the Historical Practices, Cultural Uses, and Preservation Techniques of Navajo Spinach.

In the fall of 2016, research into the common practices, cultural uses and preservation techniques began as we attempt to document the role of Navajo Spinach in the cultures of the Four Corners region of the desert southwest.


Materials and methods:


  1. Collect Navajo Spinach seeds from throughout southwestern tribal lands (Navajo, Zuni, Hopi).

I proposed to collect mature Navajo Spinach seed from wild populations (biotypes) of Cleome serrulata near Farmington, Gallup, and Zuni, NM; Shonto, Chinle, and Keams Canyon, AZ; and around Navajo Mountain, UT. These sites were historically important crop production areas and I have detailed assessments of local growing conditions, landscape parameters (elevation, seasonal temperatures, soil types, etc), and site characterizations. Collected seeds were be graded for maturity, dried to 5-6% moisture content, and stored at room temperature (20C) until used in Objective 2. Navajo Spinach seed provided by Great Basin Seed Co ( served as our control. Our preliminary work (Fig. 1) suggests there are site differences in germination so collecting seeds from a variety of locations across the region will help us identify if these differences are real. This is in agreement with the work on wild C. gynandra from Africa (Ochuodho and Modi, 2005; K’Opondo et al., 2015) who also showed locational differences in seed germination. In addition, seed sites will be videoed in October 2017 and used to be develop some of the outreach materials noted in Objective 4.


  1. Characterize the germination and growth requirements of Navajo Spinach. Detailed germination studies were conducted at Utah State University, to determine the optimum germination requirements. Wild serrulata seed contains black (mature) and white (immature) seeds in mature seedpods (Figures 12-14). For this reason, tetrazolium testing will be done for all seed collected from each location to determine seed viability. Seed lots from Great Basin Seed Co. show C. serrulata seed had 98% viability but contains both black and white seed. Our 2016 germination results indicate that chilling effects germination, but scarification (200grit sanding paper) has inconsistent results for seed germination between both Great Basin Seed lot and Canyon De Chelly seed lot shown in Figures 1 & 2. Viability of Canyon De Chelly seed has not been tested for 2016 germination trails.


Research (Ochuodho and Modi, 2005) suggests other treatments (deep chilling, gibberellins, potassium nitrate, and polyethylene glycol) can stimulate germination. Canyon De Chelly seed was used for all the germination trials in 2017 because there was abundant supply of seed. The germination tests will be applied to more locations mentioned in Objective 1 once seed is collected from those locations in 2017. Germination trials for this study include but are not limited to chilling at 4C, 7C, 10C, or 20C. A variety of scarification treatments (acid, buffing, pricking, control) were used to assess impact of germination. Soaking seed in Hydrogen peroxide (3%) for two hours was the first scarification method used, as previous methods gave inconsistent germin ation results. After soaking the seed in hydrogen peroxide, the seed was rinsed three times with distilled water to remove residue from the treatment. In addition to H2O2 soaking, some seed were also be treated with Gibberellins (GA3) at 750ppm. Seed were soaked for either two or four hours whether treated with H2O2 or not for the GA3 treated seed. Untreated seed served as the control. An additional study focusing on the Gibberellin effect on C. serrulata germination was done looking at different soaking concentrations of GA3 and with or without Promalin (GA4/GA7+BA) at 600ppm and H2O2. Each treatment was soaked in a solution (Distilled water, GA3, H2O2, etc.) for the same amount of time before being chilled at 4C, 7C, or 10C.


Five replications of 25 seeds were germinated in 40 mm petri dishes on filter paper moistened with 1.5mL solution containing 1% Captan fungicide for each treatment. Black seed were the only seed tested in the germination studies to understand the mature seed germination response to treatments. White seed previously tested at Utah State University in 2015 showed little to no germination when treated in like conditions as the black seed (Chilling for 2, 4, or 6 weeks at 4C, 10C, or 20C with/without sand paper scarification). We consider white seed to be immature and of little future interest.


Germinated seeds were counted every other day and results used to calculate percent germination, the time to 50% germination (T50 – measure of the speed of germination) and the spread of germination (T10-90; time from the 10th to 90th seed germinating - uniformity). All data will be statistically analyzed, differences noted, and variability determined. A subset of each seed lot will be assessed for seed viability via the tetrazolium test. Germinated seedling will be planted out to note growth and plant development differences. Differences of interest will be uniformity of growth, bloom timing and synchrony, seed production, size and viability, and other parameters of interest. Light test will be done if time permits where seeds will be incubated in the light (16 hr) or dark, under a range of temperature conditions (0-25C). Exposure to the temperature/light conditions will be for 10, 20 or 30 days (based on prior studies).


  1. Explore the Historical Management Practices associated with Navajo Spinach use. This history will serve two purposes (1) to understand management strategies of local wild Navajo Spinach populations, and (2) to explore the potential for commercial/home garden production for niche market as a specialty crop (fresh leafy vegetable) and a value added commodity (dyes and paints). I have researched the historic records noting how Navajo Spinach was used by the Navajo, Hopi and Zuni peoples as well as collect some oral history uses. In my readings on Navajo Spinach, I have found no complete authoritative reports on Navajo Spinach maintenance, cultivation, gathering practices, or processing procedures. A compilation of this sort of information is needed.


  1. Develop and deliver outreach products. The seed collection/germination information is the beginning steps necessary to develop production approaches to ensure the future development of Navajo Spinach as a local food crop, to grow for value-added dyes or paints, or to maintain wild populations of the plant across the Four Corners region. In the future, local collection from wild sources may ensure maintenance of local traditions. However, commercial production requires both reliable seed supplies and knowledge of seed treatment that ensure stand establishment if the species is to be grown as a leafy vegetable or for other cultural purposes. Our outreach materials will help provide this information to local Chapter Houses across of the Navajo, Hopi and Zuni Nations.


Outreach materials will be posted on the USU ( and Navajo Nation ( Extension websites and disseminated to target audiences at Chapter House meetings, high school agriculture programs, and field days. Extension Media will help us create two videos: seed collection and processing instructions, and demonstration of seed treatment practices to ensure optimal germination. We will write two factsheets as companions to the videos. During the project, presentations on the scope of the work will be presented to students and faculty at Utah State University and as invited speakers to agriculture audiences (schools, farm groups, etc.) throughout the Four Corners region, and at one professional research meetings. Slideshows, posters, and research articles will be posted on the USU and Navajo Nation Extension websites. Progress and impacts of the project will be assessed by: 1) gathering input and feedback via presentation surveys (TurningPoint), 2) outreach products developed; and 3) by gathering audience attendance information.

Research results and discussion:


  1. Collect Navajo Spinach seeds from throughout southwestern tribal lands (Navajo, Zuni, Hopi). I initially proposed to collect mature Navajo Spinach seed from wild populations (biotypes) of Cleome serrulata near Farmington, Gallup, and Zuni, NM; Shonto, Chinle, and Keams Canyon, AZ; and around Navajo Mountain, UT. During July to September of 2016, small populations of serrulata were noted for seed collection near the locations previously mentioned. One seed source was collected from Shonto, AZ in mid-October during the plants prime reproductive maturity. I was unable to collect additional seed from other locations for 2016. Locations initially identified for wild C. serrulata seed collection had little or no plant population to gather enough seed for germination trials. The 2017 C. serrulata wild populations are abundant throughout the Four Corners area. Locations for additional seed collection include Shonto, AZ; Canyon De Chelly, AZ; Gallup, NM; Zuni, NM; Near El Morro National Monument; and Fort Defiance, AZ. Seed sources out of Utah include Box Elder County and Bear Lake National Wildlife Refuge in Montpelier ,ID . No C. serrulata populations were found growing in and around Hopi tribal lands this season. Seed collection for this season is estimated to take place ending of September through mid-October 2017.


  1. Characterize the germination and growth requirements of Navajo Spinach. Five different germination trails have been done with Canyon De Chelly serrulata seed to evaluate germination requirements and used to test seed sources listed in Objective 1 after they are harvested in 2017. These studies include 4 or 8 week chilling periods with either 2 or 4 hour soaking in GA3 (4 of the germination trials). The 8 week chilling trials included a four week chilling cycle with two-week rest at room temperature then another four week chilling at the same chilling temperature. This was evaluated to determine if double dormancy was taking place in the seed. Additional germination was noted (no recorded data) from 2016 germination trials, where all germinated and non-germinated seed were planted in flats. The dormant seed was put in a cooler (4C) and rehydrated after a month’s time where additional germination was noted. The last germination test included soaking of C. serrulata seed in various concentrations of GA3. All seed trials at 20C had no germination. Statistical analysis is in progress for all germination trials.



4 week chilling with 2 hour GA3 soaking

Seed germination was higher for seed chilled in 4C for 4 weeks than at 7 or 10 C (Table 1). Overall percent germination was higher for the 4 week control trials at 4C. Time to 50% germination is consistently higher in 4C treatments than at 7 or 10C. There are inconsistent results for the uniformity of germination (T10/90) within each treatment. Treatments kept in the dark at room temperature (20C) did not germinate.

4 week chilling with 4 hour GA3 soaking

Seeds treated with GA3 had higher germination in all chilling temperatures when compared to non-GA3 treated seeds. As seen with the study conducted in 2016, germination percentage is higher in all treatments at 4C than at 7 or 10C. However, germination is slower (higher T50) at colder temperatures than at warmer temperatures (Table 1). Seed treated with GA3 and H2O2 did not germinate more uniformly (low T10/90 values) when compared to the control. Once again, treatments kept in the dark at room temperature (20C) did not germinate.

8 week chilling with 2 hour and 4 hour GA3 soaking

There was some disagreement with both 8 week chilling trials (2 and 4 hour soaking) having lower germination percentages within the first 4 week chilling cycle compared to our earlier 4 week germination studies (2 or 4 hour soaking treatments) shown in Figures 3-6. In the 8-week chill studies, both T50 and T10/90 values are higher (longer germination time and less uniform germination spread) than in the 4 week chilling trials. The highest germination percentage was from seed treated with GA3 (750ppm) and H2O2 at 4C for both 8 week trails and the 4 hour, 4-week trial (bold numbers) shown in Table 1. Treatments kept in the dark at room temperature (20C) did not germinate.

GA3 treatments test

In the four previous studies, treated seeds with GA3 is the one consistent treatment, other than temperature, that improved germination. For that reason, additional trials focused on improving our understanding of how GA3 benefits C. serrulata seed germination. Several additional GA3 treatments were applied to Canyon De Chelly seed listed in Tables 2 and 3. The 20C treatment was not used, as no seeds germinate. Treatments with greater than 80% germination are highlighted in Table 3. The highest germination percentages were noted in seeded exposed to 4C followed by 7C and then 10C treatments. Seeds treated with Promalin have consistently higher germination than all other treatments without Promalin regardless of temperature. T50 and T10/90 values are also lower than treatments without Promalin for all chilling trials. Figure 7 & 8 show the overall accumulated germination in two of the more successful germination trials where germination occurs sooner at higher temperatures (10C) than at colder (4C) temperatures. This same pattern is consistant with our 2016 results (Figures 1& 2). Treating seeds with H2O2, for scarification, does not increase germination when evaluating all germination trials. Application of low GA3 concentrations (500 or 750ppm) tends to increase germination when compared to GA3 at 1000ppm (Table 2 & 3). Seed treatments with 1000ppm GA3 can have longer time to germinate (T50) when chilled at 4C and 7C.


  1. Explore the Historical Management Practices associated with Navajo Spinach use.

Oral histories are being collected from elders in the Navajo, Hopi and Zuni Tribes where each interviewee is asked about the uses and importance of Navajo Spinach. Currently, all interviewees collected indicated that Navajo Spinach was harvested and stored for a year round diet, and was as important as corn, beans, squash, melons, and peaches. C. serrulata is found throughout Canada where it was also an important food source to the Native tribes of Canada. The spinach was collected from known locations where it thrived, but was not managed to ensure the population would be abundant the following year other than leaving enough plants to produce seed for the next season. Current distribution of Navajo Spinach throughout the Four Corners has decreased by at least 50% as mentioned by some of the interviewee’s. According to those interviewed, spinach grew in every valley near and far where it was not a concern of if there would be spinach available to harvest the following years. There is historic evidence of a practice used to preserve the Navajo spinach in Canyon De Chelly National Monument and thru where the San Juan River runs by canyon walls (Figures 10 & 11). The people living near the San Juan River and in the canyon would harvest the spinach (leaves, or juvenile whole plants), boil the plant material three times, using fresh water between each boiling period, and then mold the spinach into a patty before sticking it on the rock face to dry for storage. The drying plant removed iron on the rock face (see figures 10 & 11; bleached circular areas) indicating that iron oxides in the plant removing iron from the rock. There has not been no mention from those interviewed so far of using spinach as a dye for wool or paint for pottery as other written sources have indicated. However, none of the interviewees recall the traditional practices of pottery making or rug weaving. One interviewee is a Navajo medicine man, who mentioned the plant helps ease inching and inflammation from mosquito bites.


  1. Develop and deliver outreach products.

Outreach materials have not yet been created for this study as data and historical information are still being collected. Known reported historical uses of and early germination results have been presented to the College of Agriculture and Applied Science during the Plant, Soils, and Climate Department Seminar series Spring 2017. Components of the project have also been presented as a poster at the American Society of Horticultural Science 2017 Conference. In October 2017, we will present some of the findings at the Navajo Nation Research Conference and at the Intertribal Agricultural Council Conference. Once the study is complete, a full report will be presented to the local Native American communities that are supporting this research. They are as follows: Navajo Tribe (Shonto, AZ Chapter, Many Farms, AZ Chapter, Chine, AZ Chapter, Canyon De Chelly National Park), Hopi Cultural Preservation Office Tribal Officials, education centers and local community, Zuni Tribal Chambers council, education centers and local community, and lastly all individuals who contributed to the success of this research.Western-SARE-Final-Report-FiguresTables_171

Participation Summary

Research Outcomes

1 New working collaborations

Education and Outreach

2 Webinars / talks / presentations

Participation Summary:

2 Ag professionals participated
Education and outreach methods and analyses:

Wytsalucy, Reagan. 17 Apr 2017. Reviving Native American Crops of the Desert Southwest. Plant, Soils, and Climate Department Seminar. AGRS 141 Utah State University.


Wytsalucy, Reagan & D. Drost. 19-21 Sept. 2017. Determining Germinaion Requirements for Navajo Spinach, Cleome serrulata. American Society for Horticultural Science Annual Conference. Waikoloa Village, HI. Poster presentation.


Wytsalucy, Reagan & D. Drost. 18-19 Oct. 2017. Determining Germinaion Requirements for Navajo Spinach, Cleome serrulata . Navajo Nation Research Conference. Window Rock, AZ. NNR# 17.270 Oral Presentation.


Wytsalucy, Reagan & D. Drost. 10-13 Dec. 2017. Restoring Native American food crops (Peach and Navajo Spinach) for food security in Native American. Intertribal Agricultural Council Annual Conference. Las Vegas, NV.


Proposed outreach materials

Hurst, Winston & R. Wytsalucy. Importance of Wild Spinach to Native American populations of the South West.

Extension Fact Sheets

Methods of growing Cleome serrulata for food production.

Cook Book with Navajo Spinach- This will help promote the use of Navajo Spinach as an authentic cuisine.




Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.