Posts Tagged: nutsedge
Don't Fight It, Bite It
Rain is unusual in that it germinates weed seeds and then the need to manage them in some fashion arises. Many subtropical tree growers do not like the potential impact of pre-emergent herbicides on tree growth due to potential damage to shallow roots. Lemon growers rely fairly heavily on the post-emergent glyphosate, especially since there are cheap generic versions available. I don't know of many avocado growers who use a pre-emergent, using the natural mulching effects of fallen leaves, introduced mulch, the natural shading of the canopies and glyphosate.
I am not aware of any field studies that have shown that pre-emergents can cause root damage or reduction of tree growth or yield. There are a number of registered chemicals with different modes of action, so one would expect to see more use as practiced in other tree crops, but there is a reluctance that is based on some possible damage to trees. So, a lot of glyphosate is used and to some extent another material, glufosinate, is also used in citrus.
One of the issues that has arisen with glyphosate use has been the resistance of some weed species to this material. There are some thirty-seven species of resistant weeds in the world. In California orchards, the biggies are Hairy Fleabane, Horseweed and Johnson grass. Resistance means that you can spray the plants, even in their small stages and there's little or no effect. A non-resistant species would just wither, turn yellow and die down to the roots.
There are always plants like horsetail or purslane which have a surface that does not absorb material very well. They appear to be resistant, but aren't. Once you use the maximum dose, with a spreader-sticker or another adjuvant, the herbicide gets into the plant and it dies. Also, the key is timing, young plants being much more susceptible than bigger plants with a less absorptive surface.
This year, though with all the rains, there've been calls about not just horseweed being tough to get, but also nutsedge. Nutsedge, as far as I know, has no documented resistance, but it does have a waxy surface that gets thicker with the age of the plant. With all the weeds, people have gotten behind and the weeds have gotten out of hand and the older plants are harder to spray out. It takes more tact to get at them when they get older.
Nutsedge also reproduces from swollen underground stems called tubers or “nuts”. They aren't nuts – seeds – and some people mistake them for a grass, which they are not. They are a sedge. They reproduce primarily through the “nut” and they form lots of “nutlettes”, each of which can form a new plant. If you pull the plant up and don't get all those nutlettes, you are actually increasing the number of plants that will form. It is tricky to deal with and a good thorough spraying can control them, if done at the right stage.
It turns out that these nuts are eaten by lots of animals – pigs, chickens, humans. In the South, pigs and chickens have been used to clear fields of nutsedge before planting rice. The presents of nutsedge around the world is quite likely due to humans having spread it around the world as a food. A poor person's nut.
So, this brings me to the title of this article. Why not grow it for sale? Intercrop it with lemon. Drip irrigate the nutsedge separate from the trees and figure out the pesticide schedule and other management issues and there's a new crop for sale. Foraging for malva, nettle, mustard, pursalane, dandelions and other unconventional edible plants has become a big deal in urban agriculture. You see “wild plants” for sale in the farmers markets. Euell Gibbons has become not just fashionable but commercial. Kale has taken the country by storm. Who would have thought it?
Root System of Yellow Nutsedge
nutsedge nuts
Weed control in cool-season vegetables
Weed control in cool-season vegetables can be quite challenging. However, there are a number of...
Invasive weeds are taking a toll on wildflower displays
Sahara mustard, a resilient weed native to North Africa and the Mediterranean, is invading desert...
Invasive weeds are taking a toll on wildflower displays
UC Cooperative Extension is testing methods of removing Sahara mustard, including hand weeding, hoes and herbicide. But these are only stopgap measures meant to keep the plant at bay in select spots.
“I don’t think we’re ever going to spray the herbicide across the entire Southwest,” said Chris McDonald, UCCE advisor in San Bernardino County. “But the idea is preserving areas of value, such as the wildflower fields of Borrego Springs.”
Sahara mustard has been in California since 1927, but it wasn't until Hurricane Kathleen doused California in 1976 that it proliferated widely, according to Rich Minnich, professor in the Department of Geography at UC Riverside.
“There was this gigantic explosion of mustard, and it’s never been the same since,” Minnich said.
Anza-Borrego's tough eradication project: Cutting the mustard
Louis Sahagun, Los Angeles Times
A front-page story in the Los Angeles Times detailed the changing attractions in Borrego Springs. Tourists used to come to see a colorful display of wildflowers, but because of an invasive weed, Sahara mustard, local officials are now trying to turn visitors attention to hiking, cycling, star gazing and photography instead. UCCE's Chris McDonald, who is conducting research on Sahara mustard control, was featured in four of the nine photos that accompanied the story.
Nutgrass: Three experts' solutions to one of the worst weeds
L.A. at Home blog, Los Angeles Times
Nutsedge is commonly considered a gardeners' worst enemy, which is further proven by the draconian measures to control the weed offered by UC and other experts in the L.A. at Home blog this week. In the introduction to the problem, Cheryl Wilen, UC Cooperative Extension advisor, notes there are two kinds of nutsedge. One way to tell them apart takes a little courage.
"If you are inclined to bite into one," she said, "yellow nutsedge has a pleasant almond or brazilnut taste, while purple nutsedge does not have a good flavor."
Controlling either kind is challenging. Yvonne Savio, UCCE manager of the L.A. County common ground program, suggests extricating the weed in a way that may seem extreme.
Dig 6 inches around and under each weed and throw the weed and dug up soil into the garbage. "Don't even think of composting the weed or filtering the soil through a screen," Savio said. The weeds will come back.
Weed Control Update for Dry Bulb Onions
Weed control in onions can be challenging. Onions have various challenges that make weed control...
Onion Weed Control Materials and Timing