Worst Weed in the World

[_Keith]

This stuff essentially makes up 50% of my lawn. I have no doubt it is primarily responsible for my great struggle in getting young palms and other young plants established.

The World's Worst Weed -- and 7 Ways to Get Rid of It

http://voices.yahoo.com/the-worlds-worst-weed-7-ways-rid-it-10667073.html?cat=32

[QUINNPALMS]

I think the worlds worst weed is oxalis!

[_Keith]

I think the worlds worst weed is oxalis!

Yep, I got that one too. Plus wild Bermuda, and the worst of the worst, Ken Johnson Grass.

[Keith N Tampa (ex SoJax)]

At the risk of sounding argumentative when that's not my purpose, I submit my candidate for the worst weed in the world.

http://plants.ifas.ufl.edu/node/405

Brazilian Pepper

There are places in florida where this is essentially the only plant one can see from the highway.

[Silas_Sancona]

Thanks for the info Keith.

Kind of ironic that ive had several customers come into the nursery I work for asking how to control this stuff. Agree that Oxalis, both the creeping kind, as well as the kind that emerges from a bulb-like structure and is a scourge here in CA could tie for some of the worst weeds I have delt with.

While there are examples of "tamer" specimens of it planted around town, ive also seen unattended specimens of Brazilian Pepper spreading in vacant landscapes here. Agree that in Florida, it is a horible invasive. Don't get me started about Carrotwood, lol.

-Nathan-

[_Keith]

One of the things that makes Coco grass bad is not just its growth and pervasivness, but also this:

"One Missouri based laboratory, the Invasive Species Specialist Group (ISSG), lists the root secretions: poisonous polyphenols, sesquiterpenes, flavonol glycoside, saponin, p-hydroxybenzoic acid, p-coumaric acid, o-coumaric acid, caffeic acid and ferulic acid, a cocktail of toxins inflicted on competitors. "

[_Keith]

Full text of the article

The World's Worst Weed -- and 7 Ways to Get Rid of It Carbon Dioxide and Global Warming Fuel the Spread of Nutgrass

The Long Island Gardener, Yahoo Contributor Network
Feb 5, 2013 "Share your voice on Yahoo websites. Start Here."

• MORE:
• Weeding
• Tubers
• Global Warming

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Summer is Nutgrass season. Say your prayers.

Some call this "the world's worst weed." They're probably right. Data strongly suggests Nutgrass, aka "Purple Nutsedge," is the most destructive perennial on the planet. AgroAtlas calls it the "most malicious" species, citing its roots, which extend like tentacles, secreting poisons that damage or kill surrounding plants. With few competitors, Cyperus rotundis expands its northward reach by the hour.

In happier days, Nutgrass grew in tropical and temperate regions with mild winters, enduring sizzling summer heat and drought. But thanks to global warming, it's now thriving in places it could never grow before.

Because of the toll it takes on farmers and food, there's no shortage of government funded research to halt the spread of this noxious plant.

Labs that study it have analyzed the noxious chemicals oozing from its roots, exudates that damageTomato, Barley and Cucumber plants and other crops.

One Missouri based laboratory, the Invasive Species Specialist Group (ISSG), lists the root secretions: poisonous polyphenols, sesquiterpenes, flavonol glycoside, saponin, p-hydroxybenzoic acid, p-coumaric acid, o-coumaric acid, caffeic acid and ferulic acid, a cocktail of toxins inflicted on competitors.

Scientists have long been concerned that global warming would fuel costly global epidemics of Nutgrass and other noxious weeds. More recently, researchers at the ARS National Soil Dynamics Laboratory have found that higher levels of Carbon Dioxide in the atmosphere propelling the spreadof Nutgrass tubers. ARS is a research agency of the U.S. Department of Agriculture.

What can you do to defend your lawn and garden against this virulent, vicious species? Botanists are scrambling for answers. Here's what they know so far:

1. Handle with care. Unlike most other plants, Nutgrass spreads by nut-like tubers. They lie dormant in the soil, until stimulated. Then they sprout. Digging them up is effective, but it can backfire if you leave any tubers behind. To eradicate, you must remove all tubers, including those hidden a foot or deeper underground. 95 percent of the tubers are found in the top 12 cm of soil. But it's the last 5% that you need to watch for: A single "nut" generates more than 1.5 to 3.5 million tubers per acre in one season, according to one study. Even Nutrgrass pieces will grow into full size plants.

2. Dry and die. Few herbicides affect Nutgrass. That includes the most used weed killer on the planet, Roundup. Nutgrass tubers are just too well protected. They are, however, highly susceptible to drought. Withhold water and you can expect Nutgrass to bite the dust 4 days later. Regular cultivating and covering with plastic to block moisture can be devastating.

3. Pick the flowers. The brown blooms are what distinguish Nutgrass from similar looking weeds. Most of those seeds are infertile. In one study, more than 90% of the seed sample failed to sprout. You can avoid new sprouts by vigilantly picking flowers before they go to seed. Catching a Nutgrass plant in bloom is like seeing the gas gauge on your car is empty. Don't put this off.

4. Till with caution. Tilling or hoeing infested plots can easily backfire. The tilling action breaks up and spreads dormant tubers. Alternately till and sun-dry, instead. When you think you have the problem licked, water and wait, then re-inspect to make sure that more plants don't sprout.

5. Shake and Bake. In 2002, University of Georgia released a Nutgrass study, "What soil temperatures Will Kill Nutsedge Tubers?" Nutgrass plants exposed to temperatures greater than 50 degrees Celsius -- 122 degrees F -- fizzled. The heat and radiation applied via solarization -- sealing a plot of soil with clear plastic, trapping sunrays until temps reach levels lethal enough to basically cook anything growing under it -- is a time honored technique for weed control. Further researchpublished in 2007 found that solarization was even more effective when combined with regular tilling for 90 days.

6. Fungus Attacks. Research is incomplete, but several parasitic fungi prey on Nutgrass plants. One of the most promising: Dactylaria higginsii, said to be "highly pathogenic" to Nutgrass plants. Researchers mix fungal spores in a liquid, spray it on leaves, and wait. In tests where weather was hot and dry, the fungi failed to spread as hoped. But when it rained and humidity was high, it was the Nutgrass that did not survive. Fields where Roundup and other weed killers were applied were also tested. At those sites, the Dactylaria did not survive.

7. Be vigilant. In the case of Nutgrass, an ounce of prevention is an understatement. Once established, Nutgrass requires a massive undertaking to eradicate it. Younger sprouts are at least manageable. Learn to identify them. Then pluck diligently (tubers just sprout over and over, but with less vigor). You can also dig from underneath and remove them carefully, one by one.

DISCLOSURE OF MATERIAL CONNECTION:
The Contributor has no connection to nor was paid by the brand or product described in this content.

[Keith N Tampa (ex SoJax)]

FMC makes a herbicide called Dismiss. It's very powerful on nutsedge, but it's also highly soluble (as are all the "sedge herbicides") and might be a problem if it gets taken up by palms. I'm not much of a lawn guy so I simply now it. In the dry season the Bahia grass advances at the expense of the sedge, in the wet, it goes back the other way. Since it looks like grass, I prefer it to the species in the commellaceae "wandering Jew" family. The Bengal day flower has even evolved subterranean flowers! Eee gads, when I heard that I about fell over. But I've digressed again. Time for a good nights sleep!

[_Keith]

I used Image years ago, but it damaged so many other things, I am now terrified of it. I bought a product called Manage a while back, but am scared to try it based on my Image Experience.

[LilikoiLee]

I skipped this thread for fear our garden might come down with one of them! Lee

[Gonzer]

Nutsedge is the worst I've ever tackled in all my moons. 'Manage' is good but repeated apps are necessary. I believe the dosage is 9 grams per one gallon of water. Potent stuff.

[Mandrew968]

The worst weed for me is plane old grass--I have to cut it all too often, it comes up as a weed through my mulch, it makes my borders look like crap unless I weed eat. As if that were not enough, it sucks up all the water I apply and in my container ranches, it is by far the most invasive and most difficult weed to control--they never wanna pull and when they do, they love to take half of the dirt from the pot with them! Grass is by far my worst weed!