Can the new RPR and RTF grass varieties mean better, easier lawns? I think so…

June 3, 2013

There has been significant interest in the development of grass varieties to better meet the challenges of today’s turf conditions. The restrictions on cosmetic pesticides and outdoor water use have resulted in increased maintenance required for traditional turf grass varieties. In Ontario, turf is typically composed of cool season grasses which include Kentucky Blue Grass (KBG), Perennial Ryes and Fescues, each with both positive and negative characteristics. KBG is valued for its colour and its ability to self-repair due to its rhizomatous root structure, which is fairly short making it easier for sod harvesting. Unfortunately, this grass is more susceptible to pest problems including white grubs, chinch bugs and blue grass weevil. Its wider grass blade and shorter roots equates to a higher evapotranspiration rate, leading to increase water demand and/or early onset of dormancy in hot, dry weather.

The perennial ryes and fescues have longer roots systems, systemic endophytes (symbiotic fungal presence within the grass blade) to deter pests and have lower evapotranspiration rates compared to KBG, meaning longer periods before the onset of dormancy. The most common downside to these grass types is that they lack rhizomatous or stoloniferous root structures, limiting their ability to self-repair. Essentially these grass varieties are one seed = one plant, whereas the KBG is one seed =colony development. They are typically clump-forming and will need seeding to re-establish areas with die off or damage.

To maximize benefits and minimize challenges of all three, over-seeding existing lawns with a mixture of all three is encouraged. In recent years, there have been two new grass cultivars that capitalize on the benefits the three common cool season grass types. They are Regenerating Perennial Ryegrass (RPR) with determinate stolon roots and Regenerating Tall Fescue (RTF) with rhizomatous roots.

The determinate-stolons found in RPR grow from an auxiliary bud near the base of the mother plant and grows horizontally at, or just below, the soil surface, creating identical new plants as they grow. When RPR turf is damaged from an extreme or persistent traffic event, the determinate-stolon roots grow horizontally into the worn areas, developing roots and crown growth in the damaged area.

Regenerating Perennial Ryegrass

Regenerating Perennial Ryegrass

The rhizomatous roots found in RTF grow laterally, similar to the determinate stolons in RPR, spreading underground to grow new grass in bare spots. The ability for both of these root systems to self-repair was a characteristic previously sought after, and only common to KBG. These new varieties now have the ability to self-repair while retaining their beneficial characteristics of longer roots and systemic endophytes. Both are winter hardy and show increased drought and insect tolerance when compared to other varieties of cool season turf grass varieties. RTF’s root system can grow as deep as 1.2 to 1.8 metres to find out water sources and nutrients other grasses can’t. While RPR roots are not able to grow as deep as the RTF, they are shown to have better drought tolerance than other perennial rye grasses and can better stand wear and tear.

Rhizomatous Tall Fescue - RTF Water Saver

Rhizomatous Tall Fescue – RTF Water Saver

Guelph Turf Grass Institute Study:

The Guelph Turf Grass Institute conducted a RTF, RPR and Home Lawn Mix Trial in 2012 looking at alternative grass species for drought tolerance, weed invasion resistance and resistance to insect feeding. Three turf species were used; Rhizomatous tall fescue (RTF Barenbrug), Regenerative perennial ryegrass (RPR Barenbrug) and Home lawn mixture (50% Kentucky bluegrass, 20% perennial ryegrass 30% fine fescue). Plots of each grass species were either irrigated or non-irrigated. Both RPR and RTF showed greater insect resistance and had fewer bare spots without irrigation than the HLM. The RPR had better resistance to weeds, especially when irrigated, than the HLM, an area that RTF fell short on.
(Source: Pam Charbonneau OMAFRA Turfgrass Specialist Presentation on Landscapeontario.com from 2013 Turf Grass Symposium, Guelph ON)

So in summary, these grasses should better resist insect damage by grubs and chinch bugs, be able to fill in bare spots so weeds don’t and they will stay greener, longer, during a summer drought. I have started growing the RPR in my front yard and so far I am very impressed. Quick germination, great colour and good coverage. I applied them with compost and I threw on some bone meal in an attempt to discourage birds from eating the seed. I kept them moist during the hot days and they started germinating in four days and were almost fully germinated within the week. If you are looking for a better lawn, I would recommend trying out these new types. They may be hard to find, but worth the hunt.

From my research, a summary of the Pros and Cons for RPR and RTF:

My summary of the Pros and Cons for RPR and RTF

My summary of the Pros and Cons for RPR and RTF

 

For More Information:
http://www.barenbrug.com/rpr—regenerating-perennial-rye-grass.htm
http://www.rtfwatersavercanada.com

https://qualityseeds.ca/turf/ryegrasses/regeneratin-perennial-rye.html
http://www.guelphturfgrass.ca/
http://www.guelphturfgrass.ca/
http://www.landscapeontario.com/attach/1358539733.Sustainable_Turf,_Biological_Tools_For_Turf_Pest_Management_-_Michael_Brownbridge.pdf
http://archive.lib.msu.edu/tic/stnew/article/2012sum16.pdf

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