texas x kentucky hybrid vs. turf type tall fescue

Asked March 18, 2013, 10:44 PM EDT

We lost our Kentucky bluegrass to neucrotice ring 2 years. ago. Since then we have torn out all the grass, about 6" of the dirt, and brought in 4-6" of new topsoil. It has been sitting there since last fall and we are now ready to put in a turf. We have a wonderfully, landscaped yard and still want a pretty turf that has the appearance of a KBG. However we live in the hot, dry prairie of Pueblo West. The temperatures hover around 100 degrees and even more, and often windy conditions. (we did landscape 13 years ago before the drought). We are also on voluntary water restrictions meaning we pay more per gallon over a certain amount used. Our turf area is approximately 5000 sq. ft. My question is: Is there a better turf to use between turf type tall fescue and texas x hybrid? They both tout they are more drought resistant. What about disease resistant with the Texas x hybrid? I don't see much information about that. We do like the idea of sod as opposed to seeding which would favor Texas x hybrid. I look forward to your advice. This is the 2nd time I have posted this question. I did not receive a response the first time. I appreciate your time. Barb

Pueblo County Colorado

4 Responses

Barb,
I'm sorry it has taken so long to find your answer. I thought I had forwarded the question to our turf expert, but apparently it did not go through.

I can't answer your question about disease resistance in the 2 varieties. Dr. Tony Koski is the best source of information on those details. I will attempt to get that info from him this week.

There are a few things to consider before you plant new grass this year.
1. Have you mixed the new soil and old? Ideally, you want well mixed soil 8-12 inches deep. Layers create conditions that can trap water where the texture changes, keeping the roots from going as deep as possible. Preperation before planting can help you avoid problems later.
2. Does the topsoil contain organic matter? There is no legal definition for topsoil, so it could be anything from fully mineral (worse than Pueblo West native soil) to some percent organic matter. OM is helpful to turf root growth, moisture retention, and nutrient availability.
3. How much water will it take to successfully install a 5000 square foot lawn this year? With restrictions, is it possible? Seed and new sod need irrigation more than every other day.

Have you read our Colorado Master Gardener GardenNotes on soil? You will find them at http://www.cmg.colostate.edu/gardennotes.shtml#soils.

Again, I'll try to get the disease resistance informaiton from Dr. Koski and get back to you.

Tall fescue is totally immune to necrotic ring spot, so you will never have that disease again if you plant tall fescue. The Texas bluegrass hybrids are NOT resistant, so there is a possibility of the disease returning. Bad news is that soil removal/replacement will NOT guarantee that necrotic ring spot won't return if bluegrass is planted. The fungus is ubiquitous, so the fungus is likely present in the soil that was used to replace what you removed.

As far as water use/irrigation requirement goes, tall fescue MAY need more water than bluegrass if there is not "decent" soil 1-3 feet below the surface (i.e., if you have shale or bedrock that is below that 6 inches of new topsoil. If you have a very shallow soil, then the bluegrass will require less irrigation. If you have a deep soil (that tall fescue roots can grow into...and get water from), then the tall fescue may require less irrigation. So it all comes down to how DEEP your soil is - and it doesn't have to be "good" soil, but deep soil - and there has be some water down there (from winter snow/rain recharge, or from ground water recharge...or both).

Both tall fescue and the Texas hybrid bluegrasses will do well in heat.

Thanks,
Tony


Dear Tony-Thank you for the reply back. Still nervous on which sod to pursue...Tesas x hybrid Thermal blue or RTF turf type tall fescue. We really have difficult growing conditions and high water rates, and want to get this right! Your response indicatied deep soil for RTF. Would that still be just as necessary for thermal blue as they are both rhizomes? Would Thermal blue have more "adaptability" to soil than RTF? If they both require the same 1-3 feet depth you indicated, we will probably go with RTF because of prior neucrotic ring. But would it be worth thinking about the Thermal Blue and treating the neucrotic ring? We really are searching for drought resistance. We have about 5" of rototilled sub soil that we mixed a lot of saw dust in, and then additional 6" topsoil. Under the subsoil is still dirt......but quite hard. More information please?Thanks so musch for the advice. We'd like to sod in 2 weeks. (5000 sq. ft.) Barb

Hi Barb,
I would go with the RTF, for the following reasons:
1. You won't have to worry about NRS - ever again!
2. Will tolerate the Pueblo heat pretty well - probably as well as the Texas hybrid
3. The RTF will tolerate poor deep soil better than the bluegrass
4. You won't get thatch with the RTF...or at least it will be MANY years before you do.
5. The RTF is very bluegrass-like in appearance, so still very attractive.
6. You likely wouldn't notice a watering difference between the two of them under "real life" conditions, though research might show that the RTF has a bit higher overall water use rate (but will get deeper roots than the Texas hybrid, so can "mine" water from deeper in the soil).
7. Soil in your area can be somewhat salty; the RTF will tolerate salinity better than the bluegrass.

So, if it was my lawn, I'd go with the RTF over the bluegrass.

Thanks,
Tony