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DROUGHT DAMAGE SHOWING UP THIS SPRING

April 10, 2013

Here are some interesting pictures from Rob Elder of Omaha Organics showing the impact of the drought this spring on Omaha lawns.  Damage this bad is a problem for the lawn care people.  You will have to spring seed, but that means that you cannot put down a standard preemergence herbicide.  These spring seedings generally turn to crabgrass and other annual weeds by midsummer. You can use siduron, which will allow bluegrass and ryegrass to emerge and give you some relief from the annual weeds.  If you are planting straight Kentucky bluegrass, Tenacity (mesotrione) can help with the annual weed problem.  However, both methods are expensive and difficult to do in a commercial operation.

I suspect that these area were primarily perennial ryegrass before the drought.  This is what we are seeing in our area.  The bluegrass lawns came back pretty well after the drought because of their rhizome system underground.  Whereas perennial rye thinned out and stayed that way.

Hopefully we will get more moisture this year and return to more normal conditions for the Midwest.
 

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QUACKGRASS WAS THE BIG WINNER IN DROUGHT

November 13, 2012

Quackgrass (Elymus repens) is known for its long clasping auricles and its extensive rhizome system.  It is one of the most persistent and difficult to control weeds in cool-season lawns.  Rhizomes give this species an ecological advantage over other grasses during extended dry periods.  While Kentucky bluegrass also has a rhizome system, quackgrass has a more extensive system and will out compete Kentucky bluegrass in dry years.

This was the case in this year's drought in the Midwest.  Lawns went through an extended period of dormancy that in many areas lasted for months.  This fall, we are seeing Kentucky bluegrass lawns recover. But wherever there was quackgrass in the lawn, it has gained an even bigger foothold.

Last week, I was asked to look at a lawn that one of my students cares for through his lawn care service.  It had been a mostly Kentucky bluegrass lawn up to this year, but following the drought, nearly everything that is recovering is quackgrass from the rhizome system.

Roundup will kill it, but the problem is that Roundup generally does not translocate through the entire rhizome system.  When you reseed, there is always some living rhizome tissue and quackgrass returns.  I generally recommend repeated applications of Roundup, followed by sodding.  Even that extreme treatment generally fails, however, and the quackgrass returns.

Figure 1.  Long clasping auricles of quackgrass.

 Figure 2.   Quackgrass rhizomes.

Figure 3.  Lawn in central Iowa that is nearly all quackgrass following the drought of 2012.

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