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There's a different sort of alien invasion along the border — but the Department of Homeland Security says it's no less important in the fight to help keep part of our border secure.

Carrizo cane is a Euro import that invaded South Texas a couple hundred years ago. Since then, it's literally put down roots and made itself at home. The problem is that it's so dense and tall (up to 30 feet) that it provides the perfect cover for people seeking to enter the country illegally, either to work or to smuggle people or drugs.

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Border Patrol agents say the cane is so thick, you can be five feet from someone and not even see them. We experienced this first-hand. We had a crew out shooting video for a "Zero Tolerance" border story in Laredo. As part of that story, we were shadowing a border agent. As he made his way through one section of the thick cane, he spotted someone in the river, someone who was close to coming ashore. The person spotted the agent and changed direction, staying in the water. The agents nearby tried to get to him — but good luck with all that cane. The man was gone.

So why not just make with a weed whacker and cut the cane down? The problem is, it's such a weed that it'd back in full force within a year. You can't put pesticides on it either because they would wipe out all the other plants nearby. Researchers are now looking at what keeps Carrizo in check in Europe. They are specifically looking at bugs that feed or kill Carrizo cane. They're also trying to figure out what would happen if those bugs were introduced to South Texas.

Finally, some folks here in Laredo have offered up their own option. They want to plant trees. Apparently, shade is akin to kryptonite for Carrizo cane. Get rid of the sun and you get rid of the cane, they reason. But right now the cane is so dense that no tree has any hope of establishing itself. Some local environmental groups want to cut the cane, plant trees and keep coming back to nuture them. They say within about eight years time, you'll have trees tall enough to shade and kill the cane — as well as a clear path for border agents.

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Maggie Lineback is a Dallas bureau producer.