Sunday, June 8, 2014

yellow nutsedge eradication effort: take one

"Sedges have edges, and rushes are round, and grasses have leaves that go down to the ground."

This simple rhyme was taught to me a number of years ago as a way to distinguish among three groups of plants that look very similar. It kept running around in my head yesterday during the four hours I spent digging up yellow nutsedge on my farm.

Rowan, the Headwaters farm manager, alerted me to the problem the day before when he emailed to tell me he'd noticed nutsedge around my irrigation mainline. Not being familiar with this particular weed, I spent a while researching it on the Internet. Turns out it's s true sedge, which means it likes wet ground and often springs up around leaky irrigation systems. (Oops. But thankfully it's now fixed.)

Like Canada thistle, yellow nutsedge is rhizomitous, meaning its root system sends out horizontal rhizomes, or underground stems that sprout new plants.

yellow nutsedge with a rhizome that's sprouting a baby plant
Attacking the nutsedge now, before it has a good foothold in my fields, is critical. Over the next few months, they will be sending out lots of rhizomes and sprouting lots of new plants. Then, in late summer, each new plant will make a tuber. Next spring, all of those tubers will sprout new plants, which in turn will sprout rhizomes, and my nutsedge problem will become much, much bigger.

Nutsedge reproduces almost entirely through tubers and rhizomes, which means that over time, my entire farm could be filled with just a few clones of the same plant! If that doesn't sound like the premise for a horror movie, well, you're probably not a farmer...

The nutsedge tuber, sometimes called a "nutlet," is the small, dirt-ball looking thing in the middle of the roots.

Since yellow nutsedge makes tubers, I think it's interesting that most of the nutsedge on my farm was growing in a couple of my potato beds. As I dug around to find all the roots and rhizomes of each nutsedge plant, I had to be careful not to grab the roots and rhizomes of the other plant, the one I actually want to keep.

A potato plant, sacrificed for the cause. The tuber, called a "potato," is the small white tear-shaped ball at the end of the rhizome that's sticking out in the lower right corner of the picture.
I have a little pet theory, based in no scientific fact whatsoever, that similar or related plants grow together for a reason. For example, lettuce and thistles are in the same family, and it sure seems to me that lettuce beds often have more than their share of thistle. Now I find the tuberous nutsedge and the tuberous potato flourishing together in the same beds. Maybe it's related to soil type or nutrients or water needs or beneficial microbes... Or maybe there's no truth to this at all. It's just one of those ideas I think up as I do field work.

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