I'm a little off topic, I guess, but I planted corn in the bottoms one year in weeds and horseweeds so tall that I couldn't see the end of the field.  My wife, in the house on the hill looking over the bottoms, could only see the exhaust of the tractor sticking over the weeds.  It was a late year, the creek had been up, and I was desperate.  Everybody laughed at me, but they all were amazed at the great corn crop we had that fall. I had a perfect weed kill, and when corn got full height and green, you couldn't tell the difference in that field and conventional plantings in the area.

I have planted in some pretty tall vegatation with beans, but don't remember the details.