Friday, August 20, 2010

Grass (Zacate)

PART I: Getting Rid of It

I think you'd rather hear about hibiscus, or heliconias, but I've had limited experience with these tropical blooms. However, I've had a lot of experience with, and success with, grass. Not exactly a romantic subject, but a fact of life for almost all property owners.

At our old home in Clemson, South Carolina, we had lots of grass; too much, in fact, and we got rid of a lot of it. It was mostly fescue, but there was one big patch of centipede, and another of Bermuda (ugh!).  Lots of weeds were mixed in, including crab grass, violets, English plantain, dandelions, chickweed, and henbit, just to mention the most common. The former owner (Lanier Cawley) summed up his attitude toward grass as follows, "If it's green and you can cut it with a lawnmower, I call it grass." A sensible approach, and one we followed religiously. Grass was not to be fussed over; it provided a contrast to the shrubs, trees, and flowers, and gave space to stand back and appreciate the garden.

When we arrived at our new home site in Costa Rica we discovered a plethora of plants, but African star grass ( Cynodon nlemfuensis) predominated. Star grass, closely related to Bermuda grass (Cynodon dactylon), is an invasive exotic species, and a curse. I call it "Bermuda grass on steroids." It was introduced to Costa Rica as a forage grass for cattle. But my neighbor says his dairy cows prefer almost any grass to star grass. Unfortunately, it out-competes everything, and can take over a lot in no time. It would even give kudzu a run for its money. It multiplies by sending out runners, which are like steel cables, and can grow several inches in a day. The runners can climb twelve feet or more up a tree or fence. I have pulled up runners over 30 feet long. You can't plant any other kind of grass in it or near it, and if you should plant flowers or shrubs, you'll have to edge them at least once a month to keep the star grass from taking it over. If we left our lot for one year, when we returned I'm sure the only thing left would be star grass. Everything else would have been taken over and smothered by it.

Okay. So, before we plant any grass, or ANYTHING, for that matter, we must first get rid of the star grass. My gardener recommends two applications of Round Up mixed with diesel. This is not an option if we consider ourselves in any way, shape, or form, organic gardeners. Another way is to to dig it up. This is very slow and tedious.  Another option is to bulldoze it. We plan to do this to a section once the next dry season arrives. I'll report back on the results.
 

Black plastic put down to kill African star grass

Another option is to cover it with black plastic. This is an organic option, and can be effective. I have had various various levels of success with black plastic. The first time we tried it, we only put down one layer of plastic, did not wait long enough, and got rid of nothing. The second time it worked. We put down two layers, waited a full three months, and VOILA, the star grass was obliterated. The third time we did it (we thought we were pros now), it didn't work. Star grass can live under black plastic!!! The difference, we later realized, was that the second (and successful) time, it was the dry season. The third time, it was the rainy season.

So, to get rid of African star grass, put down a double layer of black plastic, put it down at the beginning of the dry season, anchor it with lots of stones (otherwise the high winds will blow it away), and leave it down for a full three months.

Happy gardening!

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