To block out the "Harry Potter Scary Trees" I would plant tall aquatics like Bull Rush and Cattails.

Both of those could be controled with Rodeo herbicide. Since your section of the pond is so small, I would simply aquascape the entire thing. In front of the bull rush, I would plant pickerlweed and blue flag iris. Finally, at the bank I would plant cordgrass.

That way you would have the pretty flowers of all the plants and no maintenance.

If you want fish, a different story. You would have to create a habitat more apealing to them on your side of the fence opposed to the other side.

Lastly you could create the Los Vegas pond and install a water wall (We use those in fire fighting) and at night you could play reruns of Father knows best and Ozzy and Harriet for your freinds.

All joking aside, I suggest the aquascaping route.