Grass ID puzzle

Smokindog

LawnSite Senior Member
Location
DFW area
SORRY FOR THE LONG POST but I thought it was all necessary. Pictures show about 2 years from lawn going into dormancy 10/31/17, sprig donor area hanging over wall, fill/level area this year, and actively growing 7/24/18 (year ago).

I've posted closeups of the differing colors and textures and patches of grass in this area of my lawn in the past and always get conflicting opinions of the grass types. Not a complaint, it's tough to do some things in pictures.

I'm in North Texas (DFW area) and have been working on this one area of my lawn for a couple years. I know the guy who installed the lawn in 2002 and he assures me it was all 419. I had a side lawn re-sodded in 419 last year after some construction so I've got good stand for color/texture comparison.

Based on other posts and information here I had resolved myself to the fact that the previous owner who didn't really care for the lawn had probably spread common Bermuda seed over top the 419 in this area (found a partial bag in the garage when we moved in) while it was on the market (2 years) before we purchased. Water is priced like gold around here and I'm pretty sure he didn't want the $1K water bills in the summer which I solved with a one time investment in an irrigation well.

I treated the entire lawn in February 2019 with Negate 37 for weeds and POA. Per mfg recommendation I diluted the entire bottle into a gallon of liquid and mixed my spray from there (1.5oz WG/acre). I followed up with a Prodiamine treatment (65 WDG). I did another pre-emergent treatment in late April after some leveling/fill with a soil/compost mix. I also sprigged the areas I filled using some donations from the new lawn I mentioned.

Once the sprigs had mostly covered the area I treated the sedge that I presume came in with the soil/compost with Agrisel Sulfentrazone 4F Herbicide (Sulfentrazone - 39.6% @ 1Tsp/gal/1K ft with a 1/2Tsp/gal/1Kft follow up as recommended) with NO DAMAGE to the newly grown 419! Great product for sedge IMO.

I used up left over product in the sprayer each time to spot spray some weeds and noticed some of the surrounding area also dying but not completely, there was definitely 419 left alive and well.

I did an experiment and used some left other Negate concentrate and sprayed two side by side areas demonstrating the two different grasses, one with Negate and one with Sulfentrazone.

Two weeks later the Negate area was weed free but still has both grasses and the Sulfentranzone has only the 419 remaining alive (which is good in my book as it's now spreading).

OK, here what's puzzling me.....
Negate is supposed to take out POA and Sulfentranzone is supposed to be safe on POA (IF I'm reading the labels correctly). BOTH are supposed to be safe on both common and hybrid Bermudas. What OTHER type of grass could this possibly be in Texas that comes back every year even with complete 3 application pre-emergent (I've used both prodiamine and dithiopyr over the years).

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OP
Smokindog

Smokindog

LawnSite Senior Member
Location
DFW area
OK, it stopped raining and I was able to get a picture of the "test strips". They are side by side in full TX sun! Ignore the dead sprigs lying on top, that's the remnants of edging that I blew off the drive and left behind :) And ignore the weed in the top of the Negate area, it's obviously outside the test area I sprayed :)

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That Guy Gary

LawnSite Gold Member
Location
SW Idaho
So it's a grass that was severely injured by a high rate of sulfentrazone, was green in Feb down in Texas, and blends into a short cut bermuda lawn?

Probably creeping bentgrass.
 
OP
Smokindog

Smokindog

LawnSite Senior Member
Location
DFW area
So it's a grass that was severely injured by a high rate of sulfentrazone, was green in Feb down in Texas, and blends into a short cut bermuda lawn?

Probably creeping bentgrass.
The dose of sulfentrazone used was per label for Bermuda but I hadn't considered creeping bent (cool season) which is listed as "safe" at 1/2 the warm season rate for Bermuda. Both test strips were green just before I sprayed like the Negate test strip is now. Negate label says it may have some off color and growth regulator effects on Bent but not kill so I guess Bent is a possibility.

Question though - wouldn't bent (cool season grass) already be going heat dormant on its own by this time of year in my area?

THANKS for the response! I had never considered bent grass in my area :)

EDIT - Looks like I may be on the edge of its growing zones based on this

https://bentgrasses.com/adaptation/index.html

PPS - I'm happy if that's what it is and can be selectively eliminated. Much better alternative than acquiescing to common Bermuda :)
 
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That Guy Gary

LawnSite Gold Member
Location
SW Idaho
Most cool season turf can survive heat with enough moisture. Even if they go dormant as long as they receive enough water to prevent cavitation they green up again when it cools off.

I haven't been there in decades but highs in your area are usually 90s, occassionally low 100s? Even KBG can tolerate those temps if it's a dry climate.

Humidity plus heat is the real killer for cool season turf, the higher water requirements make it difficult to prevent dormancy in the Summer without propagating fungus.
 

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