Weighted planter for water plants in ponds

To prevent the device from floating up, the smaler inner tube has to be filled with gravel, rocks or sand. close it with the small plug afterwards. 
Finally fit your plants/roots or moss in and close the whole thing with the big plug. The plugs will snap in place, no glue needed.

To be honest: a simple flower pot with some stones at its bottom and a little chicken wire on top might serve the same purpose. But since i didnt like the looks of it and had no small enough pot for verry shallow areas in the pond, i came up with this design.
 

Just fill it with gravel, fit your plant in an throw it all in your pond! It will keep your plants in place and is also easily set to an other location without digging for some roots.