Selecting the Right Turfgrass Variety for Your Yard
Southwest Yard & Garden
Reprint from 2009. Guest
contributor Dr. Bernd Leinauer,
NMSU
Extension Turfgrass Specialist
Clickable links for related columns on irrigating turf and subsurface drip irrigation!
Warm- (tan-colored) and cool-season (green) turfgrasses in late winter. Photo credit “Turfgrass Irrigation” NMSU Extension Circular 660 (https://aces.nmsu.edu/pubs/_circulars/CR660/welcome.html).
A turfgrass research plot in which different turfgrass varieties
are evaluated. Photo credit “Turfgrasses for New Mexico” NMSU Extension Guide H-508
(https://aces.nmsu.edu/pubs/_h/H508/welcome.html).
Question: I want to plant a lawn with a grass that uses less water than
ryegrass. Do you have any suggestions?
- B.L., Raton
Answer: Dr. Bernd Leinauer, NMSU Extension Turfgrass Specialist, provided
this information.
I
am frequently asked about plant selection, but this can’t be answered without
addressing two other areas: human expectations and irrigation system
performance. I hope this will clear up some general misconceptions about turf water
use.
A
plant's water requirement is a very important aspect of plant selection here in
the arid Southwest. In summer, outdoor watering accounts for 50% or more of
urban domestic water use. Turfgrasses, which can make up a large portion of our
landscapes, are consequently identified as "water guzzlers." One
might think that removing traditional grasses (like Kentucky bluegrass,
perennial ryegrass, or tall fescue) and replacing them with "low water
use" grasses (buffalograss, blue grama, bermudagrass) would conserve large
amounts of potable water. However, other factors must be considered.
New
Mexico’s climate—dry, hot summers and cold, often dry winters—can be very
challenging for plant selection. Generally, it is easier in our climate to
maintain cold-tolerant plants in the summer than drought-tolerant, cold-sensitive
plants in the winter. Therefore, cold tolerance is usually the first
characteristic considered when selecting perennial plants—from turfgrasses to
shrubs and trees. In addition to cold tolerance, turfgrasses often have to
survive and recover from all sorts of abuse from sports like football and
soccer, and regular traffic from children and pets. No wonder Kentucky
bluegrass, perennial ryegrass, and tall fescue are considered desirable grasses
for our lawns since they are the only ones that are both traffic-tolerant and aesthetically
pleasing most of the year. This brings us to our next question: Which cold- and
traffic-tolerant grasses use less water?
When
selecting plants for water conservation, it’s important to decide what your
quality and functionality expectations are. Do you want a green, playable
surface that withstands traffic almost all year, or simply a landscape with
ground cover where color or lack thereof is not important? If traffic tolerance
is not important, we can use other cold-tolerant grasses with lower irrigation
requirements than cold-season grasses like Kentucky bluegrass. Buffalograss and
blue grama are native grasses with cold tolerances that make them suitable
throughout New Mexico. These grasses will withstand mowing heights over 4
inches or can be left unmowed as ornamental grasses. Unfortunately, they can
only be used in areas that receive little or no traffic, where the main purpose
is landscape aesthetics. Furthermore, buffalograss and blue grama are warm-season
grasses that go dormant (lose green color) during mid to late fall and stay
colorless (grayish to tan-colored) until late spring or early summer. Areas
planted with buffalograss or blue grama require little or no irrigation during
dormancy. Buffalograss lawns look different from a traditional Kentucky
bluegrass or fescue turf since the plants' canopy is more open and less dense
and uniform, with more of a "meadow" appearance than a traditional
lawn.
You
may have noticed that I avoid the term “water use” and instead use the term “irrigation
requirement.” It’s our observation, particularly in residential areas, that
turfgrass areas are being irrigated well above what is required because of a
lack of knowledge of how much water is needed. The blame is put on grasses that
are labeled "high water users" when in reality these grasses do just
fine with less water. Instead of how much water turfgrasses use, we should ask how
little water they need to survive and meet our quality expectations. All
turfgrasses, including Kentucky bluegrasses and tall fescue, can survive with
less irrigation water using mechanisms that allow plants to adapt to drought. Turfgrasses
can also survive longer periods without any irrigation, even in summer. Grasses
simply go dormant and lose color (just like in the winter), but will turn green
again after the water has been turned on. We have buffalograss test plots at
NMSU in Las Cruces that have not been irrigated for 2 years, but green up for a
brief period after every significant rainfall. The plots show green color only
for a total of 4–6 weeks per year. This may not be acceptable for people who
enjoy the green appearance throughout the summer, but it shows how resilient
some grasses are. Even Kentucky bluegrass will go dormant and lose color in the
summer when exposed to drought, but will recover when rain or irrigation
resumes.
If
sprinklers are used to irrigate, a catch can audit will tell us how much and
how uniformly water is applied. A survey of irrigation audits throughout the
Southwest showed that the average residential irrigation system has a
distribution uniformity of 50%, regardless of sprinkler head type. To irrigate
all areas of a lawn adequately with a system with 50% uniformity, the amount of
irrigation water doubles compared to what "the grass needs" to
maintain adequate quality. A poorly functioning irrigation system may therefore
contribute more to wasted water than the grass species selected.
So,
before you drastically change your landscape by either completely removing the
turf or changing to a different kind of grass, consider the following: 1) What are
your quality expectations? 2) If you use a sprinkler system, conduct an
irrigation audit and learn how much water is applied with every irrigation. 3)
If you feel you are wasting water by irrigating your lawn, start watering less.
You will reach a point when the turf quality declines somewhat, but this slight
decline in appearance may be acceptable and may result in significant water
savings. 4) Consider alternative irrigation systems (such as subsurface drip)
that apply water more uniformly and efficiently than traditional sprinkler
systems. 5) Use warm-season grasses such as zoysiagrass, bermudagrass,
buffalograss, and blue grama if you feel a change in species will not affect
the purpose and functionality of your lawn.
Dr. Leinauer
added, “After several years of research at NMSU, we conclude that Kentucky bluegrass
is more drought tolerant than all other cool-season grasses and is highly
recommended for turf areas if a cool-season grass is chosen.” Find more
information on lawn care in NMSU Extension publications at https://aces.nmsu.edu/pubs/_h/#lawns
and more about NMSU’s turf research programs at https://aces.nmsu.edu/programs/turf/.
This year, the Southwest Turfgrass Association will hold its
annual conference in Albuquerque, October 15–17, 2019. Speakers from NMSU and
other universities will present on topics and latest research findings on the
sustainability of urban landscapes in the Southwest. Check it out at http://southwestturfgrass.com/.
For Further Reading
H-510: How to Perform a Catch Can Irrigation Audit on a Home
Lawn Sprinkler System
http://aces.nmsu.edu/pubs/_h/H510/welcome.html
http://aces.nmsu.edu/pubs/_h/H510/welcome.html
For more gardening information, including
decades of archived Southwest Yard & Garden columns, visit the NMSU
Extension Horticulture page (http://desertblooms.nmsu.edu/), follow us
on social media (@NMDesertBlooms), or contact your County Extension office
(https://aces.nmsu.edu/county).
Marisa Thompson, PhD, is the Extension Horticulture Specialist for New
Mexico State University and is based at the Agricultural Science Center at Los
L
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