Getting Rid of Nutgrass

I feel like it is time to discuss something that is the bane of many Texas gardeners' existence -- mine, too.  This is a weed that is utterly rampant in my flower beds.  It is common in lawns, too.  Luckily, in my case, it doesn't flourish as well there as it does in the garden.  This invasive, almost indestructible plant is nutgrass.

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Yellow Nutsedge Growing

Nutgrass isn't really a grass at all, but is, in fact, a true sedge, otherwise and more correctly known as nutsedge.  Two types are common in the US, Yellow Nutsdege and Purple Nutsedge.  The kind that grows here in West Texas is Purple Nutsedge.  These plants are easy to identify in either your grass or garden as they grow much faster and larger than lawn-grass and other weeds.  Their leaves are thicker and stiffer than most grasses and are arranged in sets of three at their base. Grass leaves grow across from each other in sets of two.  Nutsedge stems are solid and triangular;  grass stems are hollow and round and almost flat or oval.

Nutsedge Stem

What makes these plants so difficult to kill is the fact that they grow by means of tubers and rhizomes.  The tubers are often, but incorrectly, called "nuts", which gives the plant its name.  Yellow Nutsedge produces round, smooth, brown or black tubers that can be up to 1/2 inch in diameter at maturity.  Only a single tuber forms at the end of a rhizome.  This species is more common in non-arid regions.

Purple Nutsedge has red or brown scales over its tubers.  The tubers of this variety grow in chains, with several of them on a single rhizome. Since I have nearly eliminated them from my garden, when new ones pop up, it is interesting that they will often form a little row of several plants.  This is because they are growing in a chain from a rhizome buried deep in my garden soil that throws up new plants from each tuber that develops.

Yellow Nutsedge "nuts" or Tubers

Purple Nutsedge "nuts" as they grow chained together

To give you an idea of how vigorous this invader is, I generally go out on Monday morning to water my garden and pull up every single nutsedge plant I can find.  I did that this week, just like every week.  Today is Thursday.  There are already several 2 to 3 inch tall new plants in neat little rows of three or four in the garden where I had completely weeded on Monday!  Isn't Mother Nature clever?  

Purple Nutsedge--Complete Plant

Western Farm Press reports that the start of a nutsedge problem begins with one tuber in the middle of a field.  The next year, it will be a clump around 40 feet wide.  By the third year, the nutsedge will be all over the field.  That's how fast Purple Nutsedge can take over a field if left uncontrolled, according to Steve Fennimore, University of California Weed Control Specialist.  

Tubers generating rhizomes

Part of what makes nutsedge so difficult to control is the depth at which some of its tubers germinate.  "Eighty percent of the nutsedge tubers are in the top six inches of soil," Fennimore says.  "Ninety-five percent are in the top 18 inches.  That leaves 5 percent that are very deep.  It's those deep tubers that can come up and cause you to lose control of a field again if not managed somehow."  This is also why simply tilling up your garden or yard to break up the tubers isn't always effective and sometimes can be counter-productive.  A Master Gardener friend of my mother's explained that nutsedge thrives in disturbed soil because churning up the soil simply brings deeply buried tubers closer to the surface, which allows them to germinate more easily. Another trick Mother Nature plays on us unsuspecting human gardeners!

Close up of Purple Nutsedge in a Lawn

At least here in West Texas, extremely deep tubers aren't as much of a problem as they are in some parts of the country. Here, we have about 18 inches of topsoil over a base of solid cliche (limestone), so that is as deep as anything can push its roots in this area.  Still, 18 inches is pretty deep, and it really doesn't make eliminating nutgrass any easier!

Yard with Lots of Nutsedge

The fact is that nutgrass (nutsedge) isn't impossible to kill, but it is very difficult.  The only product on the market that I have found effective on the plant is called "Sedgehammer".  It works--eventually.  It takes several applications, is expensive, and can be difficult to mix up.  But it is the only thing I have found other than just digging and pulling up the individual plants.

Another reason nutgrass is so difficult to eradicate is that the tubers, if undisturbed, can lay dormant in the soil for several years.  That IS a problem here in West Texas, as this is part of the Chihuahuan Desert.  We average only about 8 or so inches of rain per year, and the area is prone to prolonged periods of severe drought.  Nutgrass loves water, but in times of drought will simply bake dry under the hot soil and wait for that precious water to return.  As soon as it gets wet again, even just slightly, new tubers shoot forth, sprouting dozens of new plants.

So, it stands to reason that the tubers are the key to nutgrass survival.  If you can limit the production of tubers, you will eventually control the nutsedge itself.  This is where I am at in this stage of nutgrass prevention. It is an ongoing battle.

Purple Nutgrass Flowers

To limit tuber production, remove small nutsedge plants before they have 5 to 6 leaves.  This is what I do every Monday. Before the plant has produced this many leaves, it hasn't formed new tubers yet.  Removing as much of the plant as possible will force the tuber to produce a new plant, forcing it to draw on its energy reserves away from tuber production and into producing new leaves and plants.

Continually removing shoots eventually depletes the energy reserves in the tuber.  The nutsedge will have to use 60% of its energy to develop the first plant and an additional 20% for the second.  But mature tubers can re-sprout more than 3 times.  Even though these newer sprouts start out weaker than the previous ones, plants can develop from them and produce new tubers unless you remove them.  In simple terms, removing the new sprouts forces the mature tuber to effectively grow itself to death.  This is a trick WE can play on Mother Nature!  (Uh-oh--visions of a margarine commercial from my childhood spring to mind!)

Mature Purple Nutsedge Chain

Another way to limit nutsedge growth is to change the type of plants you are growing.  A flower bed planted and replanted each year with annuals might be less susceptible to invasion if you replant it with a tall, dense growing ground cover or shrub.  Low-growing ground covers aren't dense enough and won't shade out the nutsedge, however.

I have seen this in action in my own garden, too.  I have one bed with very large shrub and garden rosebushes in it and no nutgrass.  I water it as often as I do the other beds, but the roses provide so much shade on the ground that the nutgrass doesn't germinate there.  It also doesn't grow in the little bed where I have a large Vitex (Chaste Tree).  This is despite the fact that on the other side of my fence, only about three feet from the Vitex, my neighbor has TONS of rampantly growing mature nutsedge.  This would normally mean that my area would be covered with the stuff, too, but it isn't.  So there must be some truth to this advice.

Purple Nutsedge Tuber System

Nutsedge doesn't grow in front of my house either, as those beds are all well-mulched and shaded by small youpon holly, large mums, and beauty-berry bushes.  Interestingly, it doesn't grow in my 4-foot by 4-foot raised herb garden, although the conditions there should be excellent for it.  Apparently, the herbs provide enough shade and take enough nutrients from the soil to make germination for the nutgrass difficult.  It also doesn't grow in my xeriscape garden as that rarely needs water and is full of large, established plants, like red yucca, rosemary, and Mexican feather grass.

Complete Purple Nutsedge Plant

The only place the nutgrass goes crazy (and this is actually getting better with meticulous care) is in my backyard flower bed that is planted with lots of low-growing, flowering annuals like petunias, geraniums, and gazanias.  These facts certainly point to the solution for a nutgrass infestation as being to provide enough shade so the nutgrass can't survive.

My Own Perfect Little Nutgrass Plant

Another solution to the nutgrass issue is to simply not water.  There is no nutgrass in my lawn per se, except on the little strip of grass in front of the bed containing the petunias and gazanias.  The reason for this appears to be the fact that we don't water the lawn.  We have a huge yard as the house sits on a very large corner lot, so watering in this climate has proven cost-prohibitive.  This time of the year, water here is at a pricey premium because we won't see any significant rainfall from now (June) until around November.  So we opt not to water the yard.  Admittedly, it means the lawn turns a dusky brown for much of the summer, but it goes a long way toward conservation of our precious water resources. And, AHA!, no nutgrass!

Nutsedge Nuts and Nutsedge Milkshakes

Interestingly, I have learned that nutgrass (nutsedge) "nuts" are completely edible.  Yellow Nutsedge is also known as the "Earth Almond" and is said to have a flavor much like that of almonds.  Purple Nutsedge tubers are edible, too, although it is more bitter than the Yellow variety.  It is still a staple of Chinese medicine today.

Jar of Purple Nutsedge Tubers

I ran across a very interesting article about the benefits ancient people gained from eating purple nutsedge nuts.  Archaeologists studying skeletons from a site near Al Khiday in the Central Sudan discovered evidence from the dental plaque on the teeth of the bodies of the hunter-gatherers buried there that they ate significant amounts of these nuts.  They are a starchy little packet of energy that also contain lysine, an amino acid naturally produced in the body and necessary to survival.

Skeleton Found with Remains of Nutsedge nuts

When I was younger, my dad encouraged me to take Lysine supplements as I was having a problem with canker sores and cavities at the time.  Turns out, he was right.  The nutsedge produces antibacterial chemicals that inhibit Streptococcus mutans, an acid-producing bacterium that breaks down tooth enamel and causes cavities.  The skeletons the archaeologists are studying showed significantly fewer cavities than would have been expected for the time period.

Where Prehistoric Plaque Containing Purple Nutsedge Fibers was Found on Teeth

It is possible that we should not be killing the nutgrass, but instead be growing it as a cash crop.  It may not be the tastiest thing we could eat, but at least we might have better teeth!

Diagram Showing Plant Structure of Nutsedge

In researching this post, I ran across lots of possible solutions to the problem of rampant nutsedge. I have found that the most effective means of controlling this pest is to provide lots of shady garden areas, pull the new shoots as they start, and to withhold water from the areas where the nutgrass would normally flourish.  It seems to be working and as long as I rethink the planting of my annual flower bed for next year, I am hoping for nearly total eradication of the issue over the next couple of years.  Personally, by integrating these activities into my usual garden chores, the question of how to control or eliminate nutgrass has been sufficiently answered.  I firmly believe these practices will work for you, too.

Drop me an email at angelasblogemail@gmail.com , or leave your comments below as to how you deal with nutgrass, what works for you, and whether or not my ideas are working for you, too.  I can't wait to hear from you!

Peace and Love Always,

Purple Nutsedge Clumps

Sources:  www.ipm.ucanr.edu/PMG/PESTNOTES/pn7432.html ; www.gardensalive.com ; www.westernfarmpress.com/university-study-finds-new-way-control-nutsedge ; http://www.npr.org/sections/thesalt/2014/07/16/331677512/this-dirty-little-weed-may-have-cleaned-up-ancient-teeth

Photo Credits:

Yellow Nutgrass Growing:  Photo credit: http://www.capitolregionwd.org/education/educational-resources/weed-spotter/;
Nutgrass Stem:  Photo credit: jerryoldenettel via VisualHunt.com / CC BY-NC-SA;
Comparison of Yellow and Purple Nutsedge Leaves:  Photo Credit:  http://slideplayer.com/slide/8107580/;  
Yellow Nutsedge Tubers:  Photo Credit:  www.articles.extension.org (a)  http://articles.extension.org/pages/66868/weed-profile:-yellow-nutsedge-cyperus-esculentus-and-purple-nutsedge-c-rotundus; 
Purple Nutsedge Chain:  Photo Credit:  www.articles.extension.org (b)  http://articles.extension.org/pages/66868/weed-profile:-yellow-nutsedge-cyperus-esculentus-and-purple-nutsedge-c-rotundus; 
Purple Nutgrass Growing:  Photo credit: kimberlysteinmann via VisualHunt.com / CC BY-NC-SA;

Sprouting Nutsedge Tubers:  Photo Credit:  www.ucanr.edu  --   http://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=6317; 

Nutgrass in Lawn Close up:  Photo Credit: http://agebb.missouri.edu/news/swnews/queries/showall.idc?story_num=5270; 

Yard with Purple Nutgrass: Photo Credit:  https://www.flickr.com/photos/18129177@N07/3909164317; 

Sedgehammer Complete:  Photo Credit:  http://ie.picclick.com/Sedgehammer-13-Herbicide-For-Purple-Yellow-Nutsedge-Covers-1-331735883995.html; 

Purple Nutsedge Flowers: Photo Credit:   http://content.ces.ncsu.edu/controlling-sedges-in-landscape-plantings;

Mature Nutgrass Chain:  Photo Credit: www.walterreeves.com --   http://www.walterreeves.com/lawn-care/nutsedge-nutgrass-identification/;

Purple Nutgrass Tuber System:  Photo Credit:  https://www.researchgate.net/figure/232682961_fig1_Figure-1-Purple-nutsedge-tuber-system-illustrating-the-relationship-between-the-initial;

Complete Purple Nutsedge Plant:  Photo Credit:  https://www.bentonswcd.org/plant/purple-nutsedge/;

My Own Perfect Little Nutgrass Plant:  Photo Credit:  Angela Fox-Thompson;

Nutgrass Nuts and milkshakes:  Photo Credit:  http://www.motherearthnews.com/organic-gardening/nutsedge-edible-zb0z11zsie.aspx;

Jar of Purple Nutsedge Nuts:  Photo Credit:  http://www.tifton.uga.edu/cpmru/Webster-phot.htm;

Skeleton with Nutsedge:  Photo Credit:  http://www.npr.org/sections/thesalt/2014/07/16/331677512/this-dirty-little-weed-may-have-cleaned-up-ancient-teeth;

Prehistoric Tooth:  Photo Credit:  http://www.livescience.com/46836-prehistoric-tooth-plaque-diet.html;

Diagram Showing Nutsedge Growth Habit:  Photo Credit:  http://www.bivocational.org/AGRICULTURE/Grasses/Data/Yellow-Purple%20Nutsedge.htm;

Purple Nutgrass Clumps:  https://courses.missouristate.edu/pbtrewatha/purple_nutsedge.htm