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Response of Different Turfgrass Types to a Dry Climate |
By Tony Koski, Colorado State University Cooperative Extension turfgrass
specialist
Different types of turf species show different abilities to withstand periods without
moisture.
Kentucky bluegrass, the dominant lawn grass in Colorado, TOLERATES
drought by going dormant. Bluegrass areas that have not been irrigated for more than a
dozen years are still alive on moisture from natural rainfall although not very pretty.
When water is again available, water slowly or cycle water on and off to avoid runoff from
dry, water-resistant soil. Watering to wet deep soil layers may be unprofitable because
deep roots may have died in the drought. Turf may have to re-grow roots at the surface as
it greens up. Note that the turf may not require as much water at first because plants of
reduced size use less water. Apply water based on examining soil moisture to avoid
over-watering, rather than watering by the calendar. Do not fertilize until the turf has
recovered.
Turf-type tall fescue AVOIDS drought by forming deep roots where soil
conditions are favorable (loose from proper soil preparation). If the drought occurs
gradually, there will be some thinning of the turf. The deeper rooted clumps survive and
the shallower-rooted ones will die out. The longer the drought (many weeks to months), the
more the loss of turf. Tall fescue has poor long-term dormancy. Once completely brown,
there will be turf thinning if it does green up again upon renewed water application.
So, tall fescue avoids drought by forming deep roots under favorable soil conditions and
Kentucky bluegrass tolerates drought by going dormant. Most grasses do both to some
extent, some more of one and less of the other. Buffalograss does both
very well - deep roots and excellent dormancy mechanisms when it runs out of water.
When water is drastically cut back or shut off on turf due to drought-imposed water
restrictions, these are the likely consequences and prospects for recovery.
Photos: Judy Sedbrook
