Abstract
Sweetgrass (Anthoxanthum nitens (Weber) Y. Schouten & Veldkamp [Poaceae]) is valued both ecologically and culturally by Mi’kmaq and other Indigenous groups. However, Mi’kmaq communities and organizations have expressed concern about sweetgrass becoming difficult for people to access due to loss of traditional knowledge, habitat degradation, climate change, and overharvesting. To help improve access and availability of sweetgrass, we assessed the viability and practicality of germinating native sweetgrass seeds for propagation and cultivation within Mi’kmaq communities with their guidance. To address our goal, we tested 1) seed storage length and temperature; 2) addition of biological additives to enhance germination; 3) methods for seed dormancy; and 4) the efficacy of outplanting seedlings into community gardens. We increased germination success up to 46% by removing seed coverings (bracts) and then soaking the seeds in water. Cold temperature storage, biological additives, and growth enhancers did not improve germination. As we learned through discussions with community members, leaf blade height, number of leaves, reproducibility, and scent are important sweetgrass characteristics for braiding and basketmaking. Bone and blood meal organic fertilizer (7-5-0) increased rhizome development for more plant growth, synthetic fertilizer (20-20-20) resulted in taller leaves, and both fertilizers increased the number of leaves. After one growing season, mature leaves from germinated sweetgrass in raised garden beds had similar or greater coumarin (scent) as their wild counterparts. Our work was the first study of sweetgrass propagation in collaboration with Mi’kmaq communities and serves to encourage the leadership of Indigenous communities to pursue sustainable and culturally respectful propagation of traditional medicines.
- Indigenous
- Mi’kmaw
- cultural keystone species
- traditional ecological knowledge
- ethnobotany
- Hierochloe odorata
- Poaceae
Sweetgrass inflorescence with flowers blooming in June in Mi’kma’ki.
| (°C × 1.8) + 32 = °F |
| cm (10,000 μm) × 0.4 = in |
| l (1000 ml or 1,000,000 μl) × 33.8 = fl oz |
| g (1000 mg) × 0.04 = oz |
NOMENCLATURE
ITIS (2024)
Sweetgrass (Anthoxanthum nitens (Weber) Y. Schouten & Veldkamp [Poaceae]), previously known as Hierochloe odorata (L.) P. Beauv., holds a profound significance in Indigenous cultures, as reflected in its use in ceremony and representation as the hair of Mother Earth. For many Indigenous groups, sweetgrass is part of the 4 sacred medicines along with tobacco, cedar, and sage. Within the genus Anthoxanthum, approximately 50 species grow in temperate and arctic regions throughout the world. These plants contain coumarin, which is emitted when the plants are disturbed, such as by drying or burning (Barkworth and Allred 2022). Because of its global distribution, sweetgrass species may have been used by non-interacting cultures (for example, Indigenous and prehistoric peoples in Europe; Bieniek 2002; Alm 2015) and interacting cultures (for instance, Christians; Quattrocchi 2006; Bączek 2017). Since many cultural practices, traditions, and teachings depend on sweetgrass, this plant is considered a cultural keystone species (Garibaldi and Turner 2004).
Traditional sweetgrass uses in Mi’kma’ki (Nova Scotia): white ash baskets with sweetgrass embellishments, created by Mi’kmaq basket makers (A); sweetgrass braid made by JA Francis (B); and smudging (C). Photo A by A Showers
The Mi’kmaq, who are indigenous to the region of Atlantic Canada, traditionally use sweetgrass for ceremonial smudges, braiding, and embellishments on basketry (Figure 1). Sweetgrass is also used as a medicine and is good for mental health, as it helps the healing process with smoke from sweetgrass purifying thoughts and the environment (Moerman 1998). An issue that Mi’kmaq communities and organizations have expressed is their concern that sweetgrass has become difficult for people to access for these cultural uses. For example, according to surveys conducted in the northeastern US (Shebitz and Kimmerer 2004) and our communications among Mi’kmaq communities, wild sweetgrass habitats are being degraded and endangered by habitat changes and overharvesting. Furthermore, some suggest that a growing disconnect of youth from traditional ways is resulting in a loss of knowledge of where and when to harvest.
Making a sweetgrass (Anthoxanthum nitens (Weber) Y. Schouten & Veldkamp [Poaceae]) braid in Mi’kma’ki.
Sweetgrass reproduction is primarily by creeping rhizomes, rather than by seed germination (Norstog 1960), which is why sweetgrass seeds are reported to be largely infertile (Klebesadel 1974). The low and uneven sweetgrass seed germination is desirable when considering plant adaptation strategies but is a major problem for introducing wild-growing plants into cultivation (Bączek and others 2021). Unlike plants that reproduce primarily by seeds, grasses have regular and fast leaf turnover, which may make grasses less vulnerable to decreased productivity associated with regular harvesting by people. Because new growth initiates from the shoot apical meristems to form leaves, stems, and roots during spring growth or to regenerate after defoliation, root propagation has been more successful than seed germination.
Sweetgrass propagation methods have been developed in central North America (Winslow 2000), and cultivars were described and released with the goal of being used ceremonially by Indigenous groups (Boe and Bortnem 1998; Winslow and Majerus 2003). However, only a limited number of studies have assessed the efficacy of growing sweetgrass within Indigenous communities. Shebitz and Kimmerer (2005) evaluated the restoration potential of sweetgrass in the Kanatsiohareke Mohawk Community (in northeastern New York State). They found that sweetgrass can be transplanted successfully and will reproduce vigorously when cultivated in garden beds suitable for home gardens, giving community members opportunity to use sweetgrass for traditions of basketry, medicine, and ceremony. Unlike in central North America, however, sweetgrass in Atlantic Canada grows where saltwater meets freshwater, requiring an understanding of sweetgrass’ unique growing needs prior to cultivation.
To help improve access and availability of sweetgrass, the goal of this study was to assess the viability and practicality of wild sweetgrass seed germination as well as propagation for growing within Mi’kmaq communities with their guidance. To address our goal, we tested 1) seed storage length and temperature; 2) addition of biological additives to enhance germination; 3) methods to break seed dormancy; and 4) the efficacy of outplanting seedlings into community gardens. As no studies of this nature have been published in the region, we assessed sweetgrass habitats and seed abundance across Mi’kma’ki (specifically, the Province of Nova Scotia) and tested seed germinability and their growth within a Mi’kmaw community. To our knowledge, this is the first published ethnobotanical study of sweetgrass in Mi’kma’ki.
Sweetgrass growth in Mi’kma’ki (Nova Scotia): sweetgrass panicle-shaped inflorescence (A); inflorescence emerging in early spring (B); mother ramets producing daughter ramets via rhizomes (C); spikelets composed of florets (D); seed enclosed by bracts (glume, lemma, palea) (E); rhizome growing aboveground (stolon) (F).
Materials and Methods
Mi’kmaq Community Guidance
We partnered with Mi’kmaq organizations (The Confederacy of Mainland Mi’kmaq and Unama’ki Institute of Natural Resources) and Mi’kmaq community members who have knowledge of sweetgrass uses, harvesting, and its habitats. The Mi’kmaq community partners who helped with this research are from different Mi’kmaq communities across Mi’kma’ki. Joining community members in sweetgrass harvesting, observing how sweetgrass is prepared and used, having conversations with community members, and planting sweetgrass in garden beds within communities uses a participatory research method. This methodology is being increasingly used in studies to provide cross-cultural opportunities for collaboration and communication (Shebitz and Kimmerer 2004; Peltier 2018). This approach was fundamental to fostering relationships with sweetgrass harvesters and community members, ensuring that the sharing of knowledge and resources occurs between our research and Mi’kmaq communities. Doing so created friendship and helped in identification of sweetgrass habitats, providing the opportunity to gain an understanding of sweetgrass characteristics.
Description of Species in Mi’kma’ki
Known as kjimsiku or weljemajewe'l in Mi’kmaw, sweetgrass is a perennial grass indigenous to arctic and temperate regions throughout the northern hemisphere. In Mi’kma’ki, the traditional and current territories of the Mi’kmaq, sweetgrass primarily grows in low-lying, moist, heavy soil in proximity to or within the upper reaches of salt marshes around the entire ocean coast and is occasionally introduced inland (Roland and Smith 1969). Sweetgrass is a mid-successional plant (Winslow 2000), thriving in sunny, open, and disturbed areas. Rushes, sedges, and other salt marsh grasses grow among sweetgrass, providing support and competition for space and height so that sweetgrass can grow tall. Sweetgrass is the first grass to flower in salt marshes, in May and June, shortly after spring growth begins because sweetgrass develops its inflorescence the previous autumn within its leaf sheaths (Figure 2A, 2B). Sweetgrass grows and reproduces quickly, producing ramets by means of its rhizomes (Figure 2C). The time of year for harvesting varies across Mi’kma’ki. The end of the season for gathering in Kespukwitk (southwest Nova Scotia) is in late July whereas in both the north shore of Nova Scotia and in Unama’ki (Cape Breton), the peak time for harvesting is in early August. In Kespukwitk, the grass will be rusty (senescence) by this time. At harvesting time, mature sweetgrass leaf blade heights range from 50 to 125 cm, with some reported to be as high as 137 cm (54 in; JA Francis’s personal observation).
Seed Collection
We collected sweetgrass seeds during sweetgrass harvesting time from a large salt marsh population in the Kespukwitk district of Mi’kma’ki (hereafter, Kespukwitk marsh) in Queens County, Nova Scotia, on 27 July 2022, 20 July 2023, and 26 July 2024. Each year we collected more than 200 inflorescences. The sweetgrass population is in the upper reaches of the Kespukwitk marsh, which is in an estuary behind a beach. The Kespukwitk marsh is regularly harvested by local Mi’kmaq community members. Other plant species within the upper marsh habitat where sweetgrass grows include prairie cordgrass (Sporobolus michauxianus [also known as Spartina michauxiana Hitchc.; Poaceae]), beach pea (Lathyrus japonicus Willd. [Fabaceae]), and salt marsh rush (Juncus gerardii Loisel. [Juncaceae]). At the freshwater edge, the Kespukwitk marsh transitions from a shrubby forest with dense alders (Alnus ssp.) to rushes (Juncus ssp.), manna grasses (Glyceria ssp.), and sedges (Carex ssp.). Within the saltwater high tide zone, saltmeadow cordgrass (Sporobolus pumilus (Roth) P.M. Peterson & Saarela [Poaceae]) and salt marsh cordgrass (Sporobolus alterniflorus Loisel. P.M. Peterson & Saarela [Poaceae]) dominate.
We also collected more than 200 inflorescences for sweetgrass seeds from a large salt marsh population in the Siknikt district of Mi’kma’ki (hereafter, Siknikt marsh) in Cumberland County, Nova Scotia, on 19 August 2022 with partners from The Confederacy of Mainland Mi’kmaq. The Siknikt marsh is in the upper part of the Bay of Fundy, borders cattle fields inland, and was historically used as farmland. The habitat is open, with no canopy cover. The Siknikt marsh is more diverse with other plant species including prairie cordgrass (Sporobolus michauxianus [Poaceae]), seaside goldenrod (Solidago sempervirens L. [Asteraceae]), fireweed (Chamaenerion angustifolium (L.) Scop. [Onagraceae]), salt marsh rush (Juncus gerardii Loisel. [Juncaceae]), curly dock (Rumex crispus L. [Polygonaceae]), silverweed (Argentina anserina (L.) Rydb. [Rosaceae]), Aster spp. [Asteraceae], hawkweeds (Hieracium spp. [Asteraceae]), and introduced species such as morning glory (Ipomoea purpurea (L.) Roth [Convolvulaceae]) and vetch (Vicia spp. [Fabaceae]) near the cattle fields.
Sweetgrass habitat with abundant inflorescences in Mi’kma’ki in May.
Our informal surveys of sweetgrass while assessing and collecting seeds across Mi’kma’ki indicate that in some habitats, the seed set is low or absent, with some habitats having many seeds and others having little to no seeds (Appendix Table A1). The inflorescence is composed of an average of 26 ± 1 spikelets, which contain 2–4 florets of which only 1–3 become potentially viable seeds (Figure 2D). We spread the inflorescences on paper towels for a few wk to air-dry at room temperature and then placed the seeds in 2-ml plastic tubes to store in the dark until we were ready to begin the study. We did not remove seed bracts (glume, lemma, palea) for storage in 2022 (Figure 2E).
Close-up of sweetgrass florets in Mi’kma’ki.
Germination Studies
We undertook 3 germination studies to assess the effect of seed storage length, biological additives, and pre-sowing treatments. Since our study aimed to assess the practicality of growing sweetgrass by Mi’kmaq community members, we conducted our seed germination using peat-based growing media (Promix Multi-Purpose LP15, Premier Tech). In 2022, we collected seeds to assess storage length prior to planting. We separated the sweetgrass seeds across 2 dark storage treatments (room and 4 °C in a refrigerator) on 4 November 2022. After the 2-wk, 4-wk, 8-wk, 3-mo, 6-mo, 9-mo, and 12-mo storage periods, we removed 50 seeds per storage treatment for planting.
We placed each seed 1.5 cm below the media surface in 47.8 cm2 seed tray pots (10 seeds per pot). We conducted the germination studies in growth chambers (Conviron Gen 1000) with a relative humidity of 60%, 14-h photo period at 350 µmols m2 s-1, light temperature of 25 °C, and dark temperature of 15 °C. We watered as needed, keeping Promix moist. We ended the germination study when no more seeds germinated after 10 d. We calculated germination percentage by dividing the number of healthy seedlings by the total number of seeds in the study. We also determined the mean germination time (MGT) with the following calculation (Ellis and Roberts 1981):
1where n is number of seeds germinated on each day, d is number of days from the beginning of test, and N is the total number of seeds germinated at the end of the test.
In addition to the seeds planted for the 4-wk storage period, we repeated the same methods using 2022 seeds but with half the seeds treated with soluble seaweed extract (Gaia Green Organics, 0-0-17) and the other half treated with mycorrhizal inoculant powder (Promix Connect, Premier Tech). We mixed the seaweed extract at 1:1 (g extract/l water) and applied this as a soil drench (2 ml per 10 seed cell) every 2 wk. We mixed the mycorrhizal inoculant in the Promix growing media prior to planting.
Our initial germination assessments were to evaluate the need for techniques to break dormancy. Fresh and viable seeds are considered dormant if they do not germinate within 4 to 6 wk under ideal conditions to support their germination (Baskin and Baskin 2004a; Baskin and Baskin 2004b). We found this to be the case from our initial germination assessment, with a mean germination time (MGT) of 7 to 9 wk. In 2023, we collected more sweetgrass seeds to assess pre-sowing techniques. We separated the seeds on 23 August 2023 across 3 different treatments: hydration (rinsing with deionized water), scarification (rinsing with concentrated H2SO4 or 3% H2O2), and control (no treatment), modified from methods by Kildisheva and others (2020), Bączek and others (2016), and Erickson and others (2016). Within those treatments we left half with the seed bracts (glume, lemma, palea) and removed the seed bracts from the other half. We also crossed the seeds with bracts still attached and seeds with bracts removed with soaking of gibberellic acid (GA3 500 ppm in deionized water; Grospurt, Acutus Enterprises).
In addition to germination assessments, we tested the viability of sweetgrass seeds collected in 2024 using a tetrazolium test, which provides an indication if the seed is alive. We removed 200 seeds from bracts and soaked them in deionized water at room temperature for 24 h and then for a further 18 h in 1% solution of 2,3,5-triphenyltetrazolium chlorine (pH 7). We then rinsed the seeds with deionized water and assessed for coloration. Viable seeds are those stained completely or partially (embryo colored).
Seedling Cultivation and Growth
To assess the efficacy of outplanting seedlings into community gardens, we compared growing media and applications of fertilizer and salt. We outplanted sweetgrass seedlings (12–20 cm leaf height) germinated from wild seeds in 2022 from the Kespukwitk marsh into 95 cm2 area pots with garden soil. We separated the pots into different fertilizer treatments with 9 replicates: 20-20-20 synthetic fertilizer, 7-5-0 organic bone and blood meal fertilizer, and no fertilizer (water as control). Applying salt (sodium chloride, NaCl) to the soil of potted sweetgrass has been suggested to help growth (Small and Catling 1999). Therefore, we separated additional pots into different salt treatments with 9 replicates: natural soil salt concentration, half the concentration, and no salt (water as control). We calculated the natural soil salt concentration from the Na soil concentration at the Kespukwitk marsh (3018 kg/ha of Na; samples analyzed by Nova Scotia Department of Agriculture Analytical Laboratory, Bible Hill, Nova Scotia), prorated to 5.35 g NaCl per 95 cm2 area pot. Using seedlings germinated from 2023 Kespukwitk marsh seeds, we separated 95 cm2 area pots with different types of growing media with 9 replicates: 70% garden soil/30% sand, garden soil, Promix (Multi-Purpose LP15, Premier Tech), and 80% Promix (General Purpose BX, Premier Tech)/20% sand.
We applied 20-20-20 synthetic fertilizer monthly to the growing media and salt comparison pots. We grew the seedlings in a growth chamber (Conviron Gen 1000) with a relative humidity of 60% with a 14-h photo period at 350 µmols m2/s, light temperature of 25 °C, and dark temperature of 20 °C. We rearranged the pots in the growth chamber every 1 to 2 wk to minimize any potential effects of spatial variation in light intensity (Poorter and others 2012).
The number of leaves, their height, and abundance of plants are important for braiding, basketmaking, and other crafts using sweetgrass. Over 3-mo growing periods (fertilizer: 23 February to 18 May 2023; salt: 24 March to 16 June 2023; growing media: 30 November 2023 to 6 February 2024) we recorded monthly measurements of number of leaves, leaf height, and number of ramets. We also monitored leaf chlorophyll (Apogee MC-100 Chlorophyll Concentration Meter), soil pH (Apera Spear pH Tester), soil salinity, and soil electrical conductivity (Tracer PockeTester). At the end of the growing periods, we harvested the aboveground (leaves) and belowground (roots and rhizomes) growth, which we dried at 70 °C for 48 h.
We planted sweetgrass seedlings germinated in 2022 in a raised garden bed with garden soil in the Wildcat Community of Wasaqopa’q (Acadia) First Nation on 29 May 2023. Seedling leaves were no taller than 72 cm with a leaf width of 0.5 cm or less and had been growing in the growth chamber since germination (4–7 mo). The garden bed was watered as needed throughout the growing season by community members. We took measurements of leaf height, leaf width, chlorophyll (Apogee MC-100 Chlorophyll Concentration Meter), and the number of leaves per plant on 21 September 2023 using a vegetative quadrant (40 cm × 40 cm with 8 evenly spaced squares). In each quadrant, we selected 3 sweetgrass plants with the tallest leaves to measure. All other remaining seedlings grown during our studies were planted in other Mi’kmaq communities, in garden beds at the Nova Scotia Community College (NSCC) in Middleton, Nova Scotia, or gifted to community members.
Mi’kmaq traditionally used the ecological cycle reflecting changes in seasons and connected the moon cycles with nature’s patterns. We planted sweetgrass seedlings in the garden beds at NSCC during the April moon, known as the birds laying eggs moon (Penatmuiku’s) and in Wildcat Community during the May moon, known as the frog croaking moon (Sqoljuiku’s) (LeBlanc and Chapman 2022). During these times is when the final frost event occurs and signals a time of warming and wetter conditions ideal for sweetgrass growth. Considering the moon phases, we outplanted the seedlings into Wildcat Community on 29 May 2023 and the following year expanded their garden bed on 29 May 2024, both during the first-quarter moon phase, which is considered the best time for planting aboveground crops.
Sweetgrass seed germination (%) at different storage periods (2 wk, 4 wk, 8 wk, 3 mo, 6 mo, 9 mo, and 12 mo), represented in weeks, at room and refrigerator temperature. Error bars are standard error (n = 5 sets of 10 seeds). Kruskal-Wallis Chi-sq = 40.059, P < 0.0001.
Coumarin Analysis
An important consideration for sweetgrass growing in community garden beds is whether it will retain its natural coumarin content. We measured coumarin from the dried aboveground summer biomass of germinated sweetgrass (after a year of growth) from the Kespukwitk marsh and Siknikt marsh that we planted outside in garden beds at NSCC in Middleton, Nova Scotia. To compare, we also measured coumarin in sweetgrass harvested from the natural salt marshes in summer and from which we gathered their seeds.
We used a modified methylumbelliferone method with coumarin standard (Scotter 2011). First, we combined sample replicates into composite samples to create enough sample material for analysis and ground the plant material to a powder using a ball mill grinder. We then extracted the coumarin from the powder by mixing approximately 2 to 5 g of sample with 250 μl methylumbelliferone internal standard and then 20 ml 90% methanol. We blended the mixture for about 30 s and placed the mixture on a shaker for approximately 30 min. We removed the supernatant, added another 5 ml of 90% methanol, and shook the mixture vigorously by hand for about 30 s. We centrifuged the mixture for 5 min at 3000 rpm and removed the final supernatant, diluting with 90% methanol to 25 ml. We filtered samples through 0.2 μm polyvinylidene fluoride to analyze on an Agilent 1260 Infinity II high-performance liquid chromatograph (HPLC) with a Zorbax column C8 with reverse phase, 5 μm 250 × 4.6 mm. We analyzed the samples in 3 analytical replicates (except 9 for Siknikt marsh in summer). Coumarin content was calculated using the following equation:
2where Cext is the concentration of coumarin in the HPLC vial from calibration curve, Vext is the methanolic extract volume (ml), and Ws is the sample weight (g).
Statistical Analyses
We performed statistical analyses in R version 4.1.3 (R Core Team 2022). We used an analysis of variance (ANOVA) to calculate significances of group differences of the MGT, fertilizer, salt, and growing media treatments, followed by a Tukey post-hoc test if significant. For non-parametric data (germination percent, leaf count), we used a Kruskal-Wallis rank sum test followed by a Dunn test if significant. We used a significance level of 0.05 for all analyses. Applying GA3 did not have significant differences for germination, therefore we pooled seeds germinated with and without GA3 within each treatment of water, H2SO4, H2O2, and control.
Influence of pre-sowing treatment combinations for each hydration method on germination percentage (%) and mean germination time (MGT).
Results
Seed Germination and Viability
With increasing seed storage lengths, we observed lower germination rates. The highest average germination rate was 38% after 2 wk of storage at room temperature and 32% after 2 wk of storage at refrigerator temperature (Figure 3). After 4 wk of storage, the germination rates were 26% for both room and fridge temperatures. After 8 wk, we observed a significant decline in germination rates with only 4% of seeds that germinated. Although the MGT at 6- and 9-mo refrigerator storage were less than the MGT after 2-, 4-, and 8-wk storage periods, the percentage of seeds that germinated was lower (see Appendix Table A2).
Our most successful treatment for germinating sweetgrass was applying a rinse with water, removing the bracts, and not applying growth enhancers, resulting in an average percent germination of 46% with a MGT of 25 d (Table 1; Appendix Figure A1). Overall, removing the bracts increased the germination percentage, but applying the growth enhancer gibberellic acid (GA3) did not influence their germinability (Table 1). We found percent germination for all hydration combinations to be significantly different, with a similar MGT (Table 2). Both biologicals of seaweed extract and microbial powder that we applied to the seeds had no impact on germination (Appendix Table A3).
Using the tetrazolium test for the 2024 seeds, we observed a viability of 39% (78/200 seeds), which is lower than the germination percent for the 2023 seeds. Assessing seed germinability over 3 y from the same location, collected around the same time, and germinated shortly after collection (less than a month) revealed germination viability of 38 to 46%.
Influence of pre-sowing treatment combinations across hydration methods on germination percentage (%) and mean germination time (MGT).
Seedling Cultivation
We observed minimal growth differences among growing media types and variable growth from salt addition with some plants dying and others growing better than the plants without salt. We observed fertilizer application to improve sweetgrass growth. Sweetgrass grown with synthetic fertilizer (20-20-20) had the tallest leaves, and sweetgrass grown with organic fertilizer (7-5-0 bone and blood meal) produced the most ramets (via their rhizomes and stolons; Figure 2F). In addition, sweetgrass growth with either fertilizer had greater numbers of leaves in comparison to sweetgrass growth without fertilizer.
Sweetgrass seedlings we planted in the raised garden bed in the Wildcat Community thrived in their care, spreading to fill the bed space (Figure 4). By contrast, we found in preliminary trials that sweetgrass that was germinated from seed or transplanted from the wild can deteriorate when grown indoors for too long under artificial lighting (after 3 mo of growth). Sweetgrass height at the end of the first growing season in the Wildcat Community (21 September 2023) ranged from 40 to 94 cm, with an average height of 66 ± 2 cm. Leaves had an average chlorophyll content of 279 ± 7 µmol/m, blade width of 0.91 ± 0.02 cm, and 6 ± 0.2 leaves per plant. Coumarin concentrations of garden bed–grown sweetgrass were similar or greater than coumarin in sweetgrass from the natural salt marshes (Figure 5). We also measured coumarin in the young, germinated seedlings but coumarin was low to zero (0–375.14 mg/g), likely attributable in part to young growth, which we confirmed by low coumarin in young wild sweetgrass growing in the salt marsh in spring (616.46– 960.02 mg/g) compared to summer (3384.50–8532.46 mg/g).
Discussion
Our goal was to assess the viability and practicality of wild sweetgrass seed germination and propagation for growing within Mi’kmaq communities with the guidance of community. Our results show that carefully removing seed bracts, separating them from infected seeds, and soaking in water can increase germination. We did not observe a difference in biological additives, gibberellic acid (GA3), scarification (H2SO4 or H2O2), or cold stratification (4 °C). Sweetgrass that we germinated from seed successfully reproduced and grew in a variety of growing media and in raised garden beds with characteristics useful to braiding and basketmaking.
With our methods, we were able to increase germination of sweetgrass seeds up to 46%, which is 4.3 to 5 times greater than in peer-reviewed scientific literature (Norstog 1960; Van Leeuwen and others 2014). Winslow (2000) reported germination rates of 25 to 50% for sweetgrass grown in the US but does not provide the scientific methodology that assessed this. When looking at plants with sporadic germination, replication is important. We used 5 replicates of 10 seeds, for a total of 50 seeds per treatment, and some of the replicates produced germination percentages of 60 to 70%. Using pre-sowing treatments of rinsing in concentrated H2SO4 and applying growth enhancers, Bączek and others (2016) enhanced southern sweetgrass (Anthoxanthum australe) germination from near 0 to 72%. But unlike southern sweetgrass, which grows in a different habitat type (dry, open forests and forest margins; Weimarck 1981), sweetgrass in Mi’kma’ki grows in salt marshes where nutrients may be restricted, which is often the case for perennials in aquatic environments with limited resources (Klimeš and others 1997). In addition, we may have exposed the seeds for too long to H2SO4, but we did not explore this method further given the impracticality for community practitioners.
Sweetgrass (A) seeding growth outplanted into the Wildcat Community garden bed on 29 May 2023 (B) and 21 September 2023 (C).
Coumarin concentrations (mg/g) in dry aboveground sweetgrass grown from seed in raised garden beds outside after one growing season compared with wild sweetgrass from where we sourced the seeds. Locations with different letters (a-b) between garden bed and salt marsh are significantly different. Diamonds represent average value (composite samples, n = 3; n = 9 for Siknikt marsh). ANOVA F = 5.765, P < 0.01.
Sweetgrass seeds with infection (A–E) compared with a potentially viable seed (F).
We observed from our initial tests that after 2 wk of storage, 32% of sweetgrass seeds germinated and we did not remove the bracts. The equivalent treatment was a control for our pre-sowing test, in which we observed that sweetgrass germinated at only 6%. If bracts are not removed, germination appears sporadic. By removing sweetgrass seed bracts before storing them, we can assess their health and viability. For example, smuts (Tilletiaceae or Ustilaginaceae) are known to periodically occur in sweetgrass seeds (Winslow and Majerus 2003). Smuts are fungal pathogens that affect grasses, causing growth of black masses, which we observed on some of the seeds we collected (Figure 6).
When we attempted storing sweetgrass seeds at 4 °C, we saw no increase in germination. In unpublished data, however, Cattani (2016) enhanced Manitoba sweetgrass seed germination to 50% with a 4 °C cold treatment. A difference in our methods may be why we observed no increase with cold treatment. We stored our seeds dry but grass seeds in the Poaceae family have a non-deep physiological dormancy, meaning they can undergo after-ripening (dormancy break) during dry storage (Baskin and Baskin 2020). Instead, storing seeds moist may have a positive effect on germinability after longer storage periods, which is reflected in the literature for some species from wet habitats (Liu and others 2011; Baskin and Baskin 2014; Heim and others 2018). However, the length of storage time may influence the preference of dry versus moist storage where long-term storage may require dry conditions (Heim and others 2018). Further research, therefore, is necessary to better understand the longevity of wild sweetgrass seeds in storage.
The time of year when collecting wild grass seeds can also affect their quality, which may have an impact on the level of seed dormancy, germinability, and storage life (Erickson and others 2016). For our germination studies, we collected seeds around the same time each year when sweetgrass blades were being harvested by community members. Collecting earlier could influence how many seeds germinate but may not always be practical for community members. Gathering seeds while already sweetgrass harvesting increased community member accessibility because time availability from work or other commitments was noted as an accessibility barrier during our discussions with community members.
The methods we employed to propagate sweetgrass complement the earlier work of Winslow (2000) by assessing the practicality of germinating local wild seeds and growing them in Mi’kmaq communities. Seeds are a sustainable source of sweetgrass for propagation in comparison to plugs, which require extraction of the whole plant including the rhizomes and may not be suitable for small populations or for culturally sensitive communities. Therefore, we encourage the use of local seeds when growing sweetgrass at a larger scale, such as for community gardens or in restoration, which requires large quantities of plants, because germinated sweetgrass will quickly reproduce after being transplanted outside.
As we observed by the successful growth of sweetgrass that we planted in additional community garden beds across Mi’kma’ki, we learned that sweetgrass may be planted in a variety of growing media and locations. This versatility suggests that sweetgrass may be a generalist species, adapting and adjusting its morphology and growth to thrive in different environments. In some instances, other plant species competed with sweetgrass in community gardens. Therefore, it is important to monitor the other species and regularly weed, especially if gathering plants from wild habitats because some native species that grow with sweetgrass, such as Baltic rush (Juncus balticus Willd. [Juncaceae]), seaside goldenrod (Solidago sempervirens L. [Asteraceae]), and silverweed (Argentina anserina (L.) Rydb. [Rosaceae]), respond just as well to fertilizer (Goldsmith and Murphy 1980). In addition, sweetgrass filling the garden beds in a community after 1 y of growth indicates that regular harvesting of mature sweetgrass may be essential to support sweetgrass growth. Much like in natural habitats, traditional harvesting of sweetgrass can help stimulate new growth (Reid 2005) in the community garden beds.
To protect and conserve the cultural keystone species of sweetgrass, it is imperative that this work be led by Indigenous communities, who maintain and care for their traditional medicines. This practice is in line with the United Nations Declaration on the Rights of Indigenous Peoples (OHCHR 2007), which emphasizes the rights of Indigenous peoples everywhere “to maintain and strengthen their distinctive spiritual relationship with their traditionally owned or otherwise occupied and used lands, territories, waters and coastal seas and other resources and to uphold their responsibilities to future generations in this regard” (article 25.1). Growing sweetgrass in community provides access to this sacred plant, giving young community members the opportunity to connect with their culture. The United Nations declaration affirms this right of Indigenous people “to maintain, control, protect and develop their cultural heritage, traditional knowledge and traditional cultural expressions, as well as the manifestations of their sciences, technologies and cultures, including human and genetic resources, seeds, medicines, [and] knowledge of the properties of fauna and flora” (article 31.1).
In 2015, the Truth and Reconciliation Commission of Canada (2015) brought forth Calls to Action and appealed to “federal, provincial, territorial, and municipal governments to fully adopt and implement the United Nations Declaration on the Rights of Indigenous Peoples as the framework for reconciliation.” Owing to the intrinsic relationships between plants and Indigenous groups, ecological and botanical studies of native plants in collaboration with community are necessary to reconciling relationships with Indigenous peoples and the environments on which they depend. Our work was the first to study sweetgrass propagation in collaboration with Mi’kmaq communities and serves to encourage the leadership of Indigenous communities to support sustainable and culturally respectful propagation of traditional medicines so that local sources are used in their restoration.
Recommendations
Our study provides some general guidelines for improving the propagation of sweetgrass from seeds, complementing previous sweetgrass propagation studies:
Wild sweetgrass seeds are available around the same time sweetgrass blades are ready to harvest. Some sweetgrass habitats may have less seed than others, and seed abundance can vary each year. Choose a large sweetgrass population with abundant inflorescences. You will need to collect more inflorescences than you want because many may be empty of seeds due to natural seed dispersal.
Some seeds will not be viable for growth because of pests or diseases that can infest plants. Infected seeds can be identified by a black, bumpy, and enlarged appearance. Aim to collect inflorescences with few infected seeds (see Figure 6) or dispose of these infected seeds.
Sweetgrass seeds will germinate without dormancy-breaking methods but can be improved by soaking in deionized water prior to planting. In addition, it is important to remove all seed coverings (bracts) to identify healthy and potentially viable seeds. Because of the small seed size, it is difficult to distinguish between a seed-filled bract and empty bracts without a microscope.
Once the seedlings are well established as pre-reproductive vegetative growth (1–2 mo of growing), transplant the seedlings into larger pots to allow their rhizomes to spread and then outplant outdoors.
Sweetgrass may be outplanted into gardens in the spring, summer, or fall before the ground freezes if they are cold hardened. The leaves will senesce, with new healthier growth emerging later in the season; or if planted in late fall, new leaves will emerge the next spring. To follow traditional growing practices, transplant sweetgrass in Penatmuiku’s (April) moon or Sqoljuiku’s (May) moon during first-quarter.
Apply fertilizer when transplanting sweetgrass to support their rhizome and root development. A 7-5-0 bone and blood fertilizer results in greater rhizome development and 20-20-20 fertilizer supports taller leaves. Both fertilizers result in more leaves.
Applying salt (NaCl) is not recommended to support cultivated sweetgrass growth.
Sweetgrass may be planted in a variety of growing media and locations, with monitoring and regularly weeding other species throughout the growing season until sweetgrass is well established and dominates.
Regularly harvest or transplant mature sweetgrass in community gardens to maintain healthy and continuous growth.
Further studies need to be conducted to identify temporal factors associated with improving the length of seed storage period. Inflorescences were produced in the community raised garden beds in the second year of growth (authors’ personal observation). Therefore, until seed storage methods are refined, communities can maintain a seedbank within their sweetgrass gardens.
Acknowledgments
This research was conducted in Mi'kma'ki, the unceded territory and ancestral homeland of the Mi'kmaq Nation. We extend our deep gratitude and respect for the opportunity to live, learn, and engage with the rich heritage of these lands. The information we present in this article received Mi’kmaw Ethics Watch approval (https://www.cbu.ca/indigenous-initiatives/mikmaw -ethics-watch/). First Nations have control over data collection processes, and they own and control how this information can be stored, interpreted, used, or shared. For more information, please refer to The First Nations Principles of OCAP®. Knowledge discussions and participation were to guide our research to best benefit communities and build rapport with community members. Therefore, we do not present the analysis of traditional knowledge here but instead consider appropriate information for the germination and growth studies to provide novel information to modern science on sweetgrass habitats within Mi’kma’ki.
Special thanks to Matt Chiasson, Charlotte Denny, Cody Boutilier, Keith Christmas, Janine Christmas, Charles Doucette, Shawn Feener, Jill Francis, Heather Ferguson, Judy Googoo, Samantha Googoo, Donald Hanson, Chau Hyunh, Crystal Jermey, Jeremiah Johnson, Anthony King, Christopher Llewellyn, Alyx MacDonald, Lenley Melvin, Jason McDonald, Leo Kepler, Chkupan Moore, Anoogwa Pictou, Denise Pictou Maloney, Zach Scantland-Griffiths, Andrea Simon, Evan Simon, Amber Showers, Melanie Smith, Samantha Watts, Pamela Westhaver, Valerie Whynot, Tuma Young, Lisa Young, and Daina Budde for your help in the field, taking care of sweetgrass in community or the laboratory, sharing your knowledge, and/or supporting this project. Thank you to The Confederacy of Mainland Mi’kmaq (CMM), Unama’ki Institute of Natural Resources (UINR), and Wildcat Community for your partnership in this work. We acknowledge the support of the Natural Sciences and Engineering Research Council of Canada (NSERC) [funding reference number 456443009].
Appendix
Descriptions of sweetgrass habitats visited in Mi’kma’ki (Nova Scotia). Given the cultural sensitivity of sweetgrass, specific locations are not explicitly disclosed.
Influence of storage period and temperature on mean germination time (MGT).
Influence of biological treatments on germination percentage (%) and mean germination time (MGT) after 4 wk of storage.
Figure A1. Cumulative average (n = 5 sets of 10 seeds) seed germination over germination time, in days, under different pre-sowing treatments.
Footnotes
Kendall RA, Francis JA, Vankoughnett MR. 2025. Germination and propagation of sweetgrass (Anthoxanthum nitens (Weber) Y. Schouten & Veldkamp [Poaceae]) for growing in Mi’kmaq community gardens. Native Plants Journal 26(1):4–21.
Photos by Rachel A Kendall unless otherwise noted
This open access article is distributed under the terms of the CC-BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/) and is freely available online at: https://npj.uwpress.org.
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