The Problem:
There is a small creek in my backyard and it's a nightmare to maintain. A lot of weeds grow there and spill over to my land, some of them growing up to three or four feet tall and are very dense. The portion of my land that is adjacent to such creek is 265 feet long. This is a warm climate (Puerto Rico to be exact), so they will always grow there. My goal is to keep them at bay, and not entirely eradicate them (I know that is impossible) Here are some photos so you can have an idea:
(Some description: the metal fence you see there belongs to a neighbor who is beyond the creek. There is no fence separating my land and the creek. And then you can see the weeds, some of which include Castor oil plants; they grow a lot here: http://en.wikipedia.org/wiki/Castor_oil_plant)
(Description: a better view of the creek with some pooled water from the last time it rained. The water doesnt get high and there is a slope in which I can plant more stuff.)
(Description: this is the part where it is the worst. Here, the weeds have grown VERY dense.)
What I Have Tried:
I have been hiring people to chop it down, but I dont want to spend money on that every single month. I have tried to lay down one of those landscape fabrics, but that was entirely futile. And I dont want to spray herbicide... it's a creek, and I dont want to pollute. Any research that I do online is for smaller problems, like pulling them out (already tried that, believe it or not), or spreading bark mulch (its too much, 265 feet, and the water of the creek will eventually swipe it), etc.
What I Plan:
My next idea will be to try and plant some tenacious shrubs that can compete against those weeds and keep them at bay. But which ones can handle this (almost everything grows here in this climate)? I had in mind Bougainvillea (http://en.wikipedia.org/wiki/Bougainvillea) since I have heard they are very hardy.
Any other idea is really welcomed.
Additional Comments:
These comments originated from the responses below.
- My main reason for battling the weeds is that they look ugly and propagate too FAST into my land, in which I'm starting a vegetable garden. Sure, not a life-threatening situation, so I will reconsider my stance a bit. Note that I want to keep them at bay, and not entirely eradicate them (I know that is impossible)
- The water doesn't get too high, even in torrential rains, which happens once every one or two months. And yes, there is a gradual slope in which I can put plants. I have included two additional photos.
- Yes, the soil inside my land is not the best. Some time ago, an excavator went through it to clear the ditch, and it compacted the land and also toiled the soil in the creek a lot (since I have started a vegetable garden, I won't allow any more excavators or heavy machinery). But the actual soil at the edge of the ditch is somewhat loose and easy to toil and with good drainage.