Research: Sorghastrum nutans

Sorghastrum nutans (Indian Grass) in Winter photo by Matt Lavin

If you are on our email list you may have received an email recently extolling the virtues of Sorghastrum nutans, or Indian Grass.

You may have heard about allelopathic properties attributed to Sorghastrum nutans. This means that, similar to Juglans nigra (Black Walnut), the plant exudes plant growth regulating chemicals that inhibit plant growth around them.

In some cases this is true but other research has shown that the presence of Sorghastrum nutans can actully promote the growth of some native plant species.

In a 2000 study, Heather N Parker’s Masters thesis explored “Potential Allelopathic effect of several grass species on Native Missouri Prairie Plant Species.”

Interestingly in this research, Parker examined not only if Sorghastrum nutans presence inhibited other plants form growing but also examined whether or not the presence of other native grass species would inhibit the growth of Sorghastrum nutans.

Asclepias tuberosa (Butterfly Weed)

Parker found the presence of Sorghastrum nutans extracts from the shotts actually enhanced the growth of Butterfly weed (Asclepias tuberosa) and Big Bluestem (Andropogon gerardii). However chemicals exuded from the roots of Sorghastrum nutans did limit the shoot growth of Asclepias.

According to Andrea Silletti and Alan Knapp, not much research has been done on Indian Grass because it is considered an equivalent of Big Bluestem (Andropogon gerardii) and researchers have long assumed that they will respond the same to varying conditions in their habitat and cause similar changes to the habitat.

Parker’s research did show a difference in the effects of the presence of these two grasses demonstrating, for example, the presence of Bothriochloa bladhii (caucasian bluestem) affected the germination rates of Big Bluestem, but not that of Indian Grass. She also found the presence of Indian Grass actually enhanced the growth of Big Bluestem shoots.

Silletti and Knapp’s <a href=”http://&lt;!– wp:paragraph –> <p><a href=”https://www.researchgate.net/scientific-contributions/ANDREA-M-SILLETTI-2013335600″>Silletti</a&gt; and <a rel=”noreferrer noopener” href=”https://sustainability-innovation.asu.edu/person/alan-knapp/&#8221; target=”_blank”>Knapp’s</a> <a rel=”noreferrer noopener” href=”https://link.springer.com/content/pdf/10.1023/A:1020320214750.pdf&#8221; target=”_blank”>2002 stud</a>y covering 15 years of data collection, revealed that Indian grass cover increased with more fire and fluctuated in response to precipitation more than any other factor while Big Bluestem cover seemed to fluctuate in relation to temperature. Perhaps most fascinating was that as biodiversity of plant species increased in a prairie, the presence of Big Bluestem decreased and that of Indian Grass showed relatively no change. Their research demonstrates that these two species will respond differently to the ecological changes of climate change and reinforce what Parker demonstrated which is that they behave differently in the environment. </p> 2002 study covering 15 years of data collection, revealed that Indian grass cover increased with more fire and fluctuated in response to precipitation more than any other factor while Big Bluestem cover seemed to fluctuate in relation to temperature. Perhaps most fascinating was that as biodiversity of plant species increased in a prairie, the presence of Big Bluestem decreased and that of Indian Grass showed relatively no change. Their research demonstrates that these two species will respond differently to the ecological changes of climate change and reinforce what Parker demonstrated which is that they behave differently in the environment.

In other research, Sorghastrum nutans has been assessed for its usefulness in phytoremediation, the process of using plants to clean toxins from soil and water. This study examines the connection between pH and the ability of Indian Grass to absorb chromium from waste water and how its effectiveness compares to other methods out there and found it to be comparable.

Andropogon gerardii (Big Bluestem) Photo: Matt Lavin

Nighttime lighting was at the heart of this 2017 study by Flowers and Gibson in the Journal of the Torrey Botanical Society. This research examined the effects of light pollution (artificial nighttime lighting) on Panicum virgatum (Switchgrass) and Sorghastrum nutans (Indian grass) as well as a couple of European species. The researchers found that nighttime lighting has an effect on “plant height, biomass and leaf number”.

Finally, this research examined the impact of urban pollinator and native plantings on remnant native plant diversity in urban areas. The researchers rated plants based on their likelihood to influence existing remnant native plant populations after being planted in home native plant and pollinator gardens. Sorghastrum nutans was shown to have a strong likelihood to influence remnant native plant diversity by escaping the garden setting.

We all know there are so many factors to consider when choosing plants for your particular project. One more way to investigate the impact you may have on the piece of land you have become responsible for is to check out any research being done on that species. Doing this may give you some new factors to consider or some new criteria to help you make decisions.


References:

Parker, Heather N., “The Potential Allelopathic Effect of Several Grass Species on Native Missouri Prairie Plant Species” (2000). MSU Graduate Theses. 60.
https://bearworks.missouristate.edu/theses/60

Silletti, A., Knapp, A. Long-term responses of the grassland co-dominants Andropogon gerardii and Sorghastrum nutans to changes in climate and management. Plant Ecology 163, 15–22 (2002). https://doi.org/10.1023/A:1020320214750

Nicholas D. Flowers and David J. Gibson “Quantified effects of artificial versus natural nighttime lighting on the Eurasian grasses Bothriochloa bladhii (Poaceae) and Bothriochloa ischaemum (Poaceae) and the North American grasses Panicum virgatum (Poaceae) and Sorghastrum nutans (Poaceae),” The Journal of the Torrey Botanical Society 145(2), 147-155, (6 March 2018). https://doi.org/10.3159/TORREY-D-17-00038.1

Johnson, A.L., Fetters, A.M. and Ashman, T.-L. (2017), Considering the unintentional consequences of pollinator gardens for urban native plants: is the road to extinction paved with good intentions?. New Phytol, 215: 1298-1305. https://doi.org/10.1111/nph.14656

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: