How To Kill Your Lawn Based On What I Learned From A Death Struggle With A Zombie Weed

This year, all I wanted to do was join other water conscious Californians and kill my lawn.

So a few months ago I gathered thousands of square feet of cardboard from behind a furniture store, spread it across my front yard, smothered every blade of grass visible and shoveled half a foot of compost and wood chips on top.

The plan was to feed the long neglected soil by giving worms and fungi something to munch on. To create a healthy, clean slate to start building a low water, native landscape. The hope being that it’d become a refuge for bugs, birds and lizards, and increase the biodiversity just a bit in our San Fernando Valley neighborhood that’s mostly sterile lawns.

But months later, this is what the yard looks like.

Patches of purple nutsedge have established themselves across what used to be my derelict front lawn.

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Jacob Margolis

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LAist

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It's covered in thick patches of green that keep popping up, even after my wife Rachel and I spend hours pulling up plants by hand.

A quick ID by the Seek app last week showed me that what we were dealing with wasn’t the grass that was there before, but something called purple nutsedge. I inadvertently created the perfect environment for it to flourish.

And an online search about it left me devastated.

Say hello to one of the world’s worst weeds

After all that work to do right by our yard, we are now dealing with what UC Riverside expert Milton E. McGiffen, Jr. called one of the “world’s worst weeds,” because it’s so difficult to get rid of.

New plants spread underground via the base of each nutsedge.

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Jacob Margolis

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Believed to be originally from India, it’s now spread around the world, and there’s a good chance you’ll come across it here in Southern California. It could already be in your yard.

Purple nutsedge can survive drought conditions, hot temperatures and has a vigorous root system that can creep down more than three feet into your soil.

Chop up the roots by tilling or trying to dig them up and the weed just spreads. The tiny little bits of tubers that get left behind multiply. It’s possible for the plant to produce more than 35,000 pounds of underground material per acre, according to the U.S. Department of Agriculture.

A new purple nutsedge sprout coming up through compost.

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Jacob Margolis

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No doubt a pest for gardeners, it can be a devastating nuisance for farmers. Dense matts of sedge have been documented to have reduced yields of corn by up to 30% and barley yields by as much as 25%.

Up in Ventura, they pop up all over strawberry fields, outcompeting the plants and destroying the thin black plastic with sharp tips that easily pierce through.

Oh, and herbicides aren’t a sure fix.

I’ll admit, when I learned about all of this, I spiraled a bit.

I considered dumping gallons of glyphosate all over everything, flame weeding (maybe inadvisable because of the compost and wood chips), or hiring a team of excavators to just scoop all the soil away.

But rather than let this devolve into a whacky and entertaining Caddyshack situation, I called some experts to help me and better understand this Terminator of plants.

How to fight the zombie weed

“It’s definitely one of those top difficult weeds that homeowners are going to deal with in their yards,” said Chris McDonald, invasive weed expert and natural resources adviser with the University of California Division of Agriculture and Natural Resources.

The purple nutsedge loves the perfectly moist environment that the wood chips provide even during warm, dry weather.

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Jacob Margolis

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I asked him how screwed I was.

“Not entirely,” he said. “If you spend a decent amount of work and a lot of effort in the next two years, you should be able to get it under control.”

Two years.

McDonald explained that I’m essentially in a war against the tubers, or nutlets, which are at the base of each plant. They’re how purple nutsedge spreads underground.

I pulled up a few and you can see new plants connected to old roots.

On the left, you can see the root connecting the more established pieces to the newer baby plants.

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Jacob Margolis

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Here are the treatment options:

1. Cover the entire space in thick black plastic and let it sit for multiple years, smothering the weed.
2. Repeatedly treat the yard with chemicals like glyphosate or sedgehammer.
3. Install plants with thick canopies (like pigeon point coyote brush, not white sage) that’ll shade out the nutsedge over time.
4. Regularly go through and pull out as many of the pieces of sedge and their nutlets as possible. 

But maybe we're thinking about weeds in our yards all wrong

“I’m going to really ask you why nutsedge bothers you,” said Shawn Maestretti, founder of Studio Petrichor, which often designs the type of landscaping I'm going for.

I’d called him and his colleague Leigh Adams to ask about how the weed might impact my lofty design plans.

I told that that I find it upsetting that the nutsedge is there because after so much work building an ideal base for what I want to install, I’m now dealing with a stubborn interloper.

“It may not be perfect. None of it’s perfect,” said Maestretti. “What are we willing to surrender to? It’s here. It’s there.”

The questions were surprisingly deep for a chat about plants. But the truth is that the pursuit of the perfect yard, free from weeds and meticulously manicured, is what lawns have long been all about. It's a system made possible by using lots of the stuff (pesticides, herbicides and monocultures) I’m trying to move away from, as I want to promote biodiversity on our lifeless suburban property.

When allowed to spread, purple nutsedge creates thick patches of green.

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Jacob Margolis

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LAist

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This type of conversation is one that Maestretti and Adams often have with clients who are trying to wrap their minds about what a lawn-less yard actually means.

“There is no such thing as a no- to low-maintenance garden. In fact, 90% of the success and sustainability of any project happens post construction. Meaning your ongoing relationship is key,” Maestretti said.

“So if there are certain plants in the garden that you’re not crazy about being there, you slowly remove them. And start nurturing the plants that you want there and your ongoing relationship.”

The goal is to slowly remove the weed over time, exhausting its stores. And on that front, I've got some good news.

Because I spread so much mulch across the yard and the sedge has yet to fully establish, I can still easily dig my hands into the soil and pull up a large number of weeds and nutlets in one go. That’s giving me hope that I can get things under control if I move fast enough.

Later this year, I’m also going to put in plants with dense canopies that’ll help shade out the nutsedge.

Maestretti and Adams said they’re partial to Bruce Dickinson California buckwheat.

“I think this is a positive. The fact that you can start pulling it out gently and slowly removing it before you start planting. You’ve got all summer. It may not be perfect. None of it's perfect,” Maestretti said.

And I can use summer to my advantage. Purple nutsedge loves water. Which is why it’s often found among well-irrigated crops and at the low points in fields where water may pool. As the hot season progresses and I refuse to water my front yard, some of it might die off. Though, the nutlets and tubers could persist for years without irrigation.

I’ll have to see what happens when the rain shows back up later this year.

It’s going to be a process.

How to prevent this from happening to you

I’ll try to be zen about it, but it’s still irritating.

Purple nutsedge has managed to travel under four-inch-thick concrete and start to come up through cracks all over.

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Jacob Margolis

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LAist

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I’m not completely clear how the nutsedge arrived on my property, but I think it was from the pile of wood chips a tree trimmer dropped off. I’d never seen the weed in our yard before and as the rains picked up, it sprouted all over the pile and the pile alone.

It’s possible that when they were trimming a tree someone tossed in yard waste that got mixed in and then spread to my yard.

“It’s a good cautionary tale to make sure the amendments you’re bringing in in your lawn and garden aren’t bringing in weed seeds,” said Brad Hanson, another weed expert with the University of California.

To do that, try buying your amendments from a source that tests the product before they ship it to you. It’s not a 100 percent guarantee, but maybe it’ll help you avoid what I ran into.

That said, I’ve gotten lots of free wood chips before without any problems. It’s a gamble.