Heritage Lawns and Irrigation

A little side note that I found intersting on this prolific weed is that it is edible and pretty widely used in other parts of the world. Apperantly in Spain the nutlets (called tiger nuts) are used as kind of a sweet tea called Horchata. I knew something this common had to have other uses. Mother nature proves again that everything has its purpose. Just wish it wasn’t in our lawns. You can find out more at http://en.wikipedia.org/wiki/Cyperus_esculentus

"The Weed from Hell"

Yellow Nutsedge with Seed Heads

Nutsedge in a Lawn

Yellow nutsedge (a.k.a. watergrass) is going strong all over Kansas City lawns right now due to the wet spring and hot temperatures.  This weed is the “Weed from Hell” for homeowners and lawncare companies.  Nutsedge is so tough and prolific that even a product that kills everything it touches, like Round Up, won’t control it.

If you notice tall grasses that stick up above your lawn and are lighter in color than your grass, you’ve got nutsedge.  Though it looks like grass, nutsedge (also called nutgrass or swampgrass) is neither a grass nor a broadleaf weed.  It is a variety of weed called sedges.  Nutsedge can reproduce by seeds but it also produces rhizomes (stems that grow underground and sprout new plants) and tubers (which store food and also produce new shoots.)  These tubers are also called “nuts” or “nutlets” and that is where the plant gets its name.  This system of underground rhizomes and nutlets make nutsedge hard to kill.

Unfortunately, once it is established, it is not easily controlled.  According to the latest study from the University of California, Davis, a nutlet can reproduce seven to eight times after each new plant is removed by pulling or spraying before it reaches the six-leaf stage.  After a plant reaches the six-leaf stage it is mature enough to start producing more nutlets, which means more plants next year.

With this new information the latest protocol to control nutsedge is to spray with products like Sedgehammer or Dissmiss and/or pull the plants before they reach maturity.  This is quite the opposite from previous recommendations in which studies found that if you wait until the plant is mature you get better kill and it won’t send up so many new young plants.  Now we understand why we kept having more problems each year, we were trying the win the battle by controlling the top but were losing the war by letting it produce more nutlets for next year.

So, the long and the short of it is – getting yellow nutsedge under control will require a team effort.  We will spray every time we treat and you will have to pull every time you spot one in the lawn.  If we beat it back 7-8 times we will make headway on reducing the population next year.  If you want to read the entire study it can be found here http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7432.html

The White Grub

There is a small window of time at the end of July and the beginning of August when grubs are most easily killed.  If you haven’t gotten your grub treatment down yet, don’t wait.  In a few weeks, you’ll see the damage, but by then it will be too late the damage has been done.  This year, the hatch of the 2010 brood is estimated to be the weeks of July 25^th -Aug. 5^th, based on peak flight of the adult beetles that occurred around June 25^th, according to the Kansas State University Entomology Department.  

This is the time of year that the grubs emerge from their eggs and burrow up into the top layer of soil where they eat the roots of the grass.  They are easiest to kill in this early stage of development.  In early fall, the grubs will begin to burrow four to eight inches into the soil away from the cold. They will return older and hardier in the spring and will cause more damage then. 

White grubs in lawns are the larvae stage of common beetles like the June bug and the Black Masked Chafer. These root eating larvae are found throughout Kansas and are a perennial problem in lawns in the Kansas City area.  We generally don’t see damage from grubs until the end of August or first of September because they feed on the roots you can’t always tell they are there until the damage is done.

Grub Damaged Lawn

If you notice brown patches in your lawn that look a lot like drought stress, you may have grubs.  Because the grubs feed on the roots, the grass begins to die and the ground will feel soft or spongy.  The green grass next to the damaged areas may lift up just like carpet. 

You can check to see if you have grubs by digging up an area that’s showing signs of grass browning.  Dig a one foot by one foot area of your lawn to just below the roots.  Pull back the turf in these suspect areas, in particular the marginal areas where brown grass meets green grass, and look for the grubs.  Usually a population of about 10 or more grubs per square foot will lead to browning of the lawn.  

Another sign of grubs is damage from skunks and raccoons digging up lawns in search of grubs to eat. This usually happens at night. Moles may or may not be feeding on grubs so are not a reliable indicator of grub problems.

If you suspect you have a grub problem the important thing is to do something about it in the next few weeks. That’s when they’re the most susceptible because they are near the surface.  Once they burrow down 4 – 8 inches, they are out of reach.  Call us if you suspect grubs and we can confirm your diagnosis, treat if needed, and start helping your lawn recover.