If the customer requires the cattails to be cut monthly and there is no place on site to leave the cattails, politely inform the customer that in the least they need to pay for dump/hauling fees for the cattails, since that was never covered in the original bid and it has became an issue that affects others. The client should be more than willing to adjust a little to allow for removal if it is causing problems to others. BTW, how large of an area and how many cattails are we talking about here? I don't think I've ever saw a situation where cattails grow unless it's standing water and probably a drainage problem to begin with. We have a couple commercial locations with drains along the road that do have cattails, they are growing in areas where the state road won't clean out the drains.