I've decided to see just how long the torpedo grass can remain viable with no water and no soil. The picture below was taken 8/5/2013. The rhizomes were dug up from a pile of dirt my son-in-law had behind his fence after putting in a pool. These rhizomes were initially dug around July 15, 2013 and simply left in a pile of dirt. I moved that dirt to another area on Aug. 1st, 2013. As the torpedo grass stolons come through the dirt and put out green leaves that I can recognize I dig them up. From experience I know how tough torpedo grass truly is. These rhizomes have had their life cycle disrupted for almost a month, but are still very viable. These have been buried in moist soil, but with no leaves. Yesterday I was wondering just how long these things could survive without water or nutrients. I placed a few rhizomes in a cardboard box and intend to leave it in my garage until they are dead, dead, dead. My plan is to periodically (probably monthly) take a rhizome portion and place it in water to see if it will sprout. I'll update the results here on this page.
Photo from August 5, 2013
I see that you can't read the text in the picture, so I'll repeat it here. The top rhizome is 12" long, although broken off at both ends. It extends beyond the picture to the right. Only about 1/2 of it is shown. I've read they can extend several feet underground before surfacing. I know from experience that they can go from my lawn underneath my sidewalk into the flower beds on the other side. Also, note the multiple sprouts emanating from the left broken end. That is why pulling torpedo grass often appears to multiply the infestation.
Most weed killers, even Roundup and equivalents will only kill the rhizome back 2 or 3 nodes. That wouldn't even kill 1/2 the 12" rhizome in the upper portion of this picture. It extends to the right outside the photo frame.
I read a lot of information on the web about torpedo grass. Much is vaguely correct, but much is absolute nonsense. As you probably know, you can believe everything you read on the web! I'm not an expert, but have a lot of experience, and have read quite a lot, both good and bad. Here is a link to a real expert, well known throughout southern LA. If you want the facts about torpedo grass and how to best control it, I suggest you read this column by Dan Gill.
An expert's advice on torpedo grass.
Photo from August 5, 2013
Most weed killers, even Roundup and equivalents will only kill the rhizome back 2 or 3 nodes. That wouldn't even kill 1/2 the 12" rhizome in the upper portion of this picture. It extends to the right outside the photo frame.
I read a lot of information on the web about torpedo grass. Much is vaguely correct, but much is absolute nonsense. As you probably know, you can believe everything you read on the web! I'm not an expert, but have a lot of experience, and have read quite a lot, both good and bad. Here is a link to a real expert, well known throughout southern LA. If you want the facts about torpedo grass and how to best control it, I suggest you read this column by Dan Gill.
An expert's advice on torpedo grass.
What I learned from this experiment was that these rhizomes dry out fairly quickly when not on the ground or in the dirt. I placed these rhizomes in a cardboard box in my garage expecting to check them in a few weeks to see if they were still viable. I can't remember how long it was before I checked, but not over 3 weeks and they were already dead, dead, dead. They had dried up and were beyond any hope of sprouting. What that tells me is that if you can get the beasts out of the ground they will dry up and die fairly quickly. If in the ground, even without leaves, they will live indefinitely.
ReplyDeleteI've just pulled up a whole large flower bed infested with this rhizome. Weed barriers foster growth and encourage the spread of runners due to the retained moisture. The sharp torpedo ends of the runners poke right through weed barrier which then makes it impossible to yank the entire rhizome. If ANY small piece is left in the ground, it will grow. Also, the runners do get around 1ft deep, especially where nutrients are rich around a plant's root ball. Otherwise, runners are 6 inches or less from the surface.
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