It can be hard, difficult and expensive. It depends on what you really enjoy. When you have fish, the water looks like pea soup, and you never see a fish for the algae, it can be down-right discouraging. But, you put in some elbow grease, the water clears and the fish follow you around the pond hoping for a hand-our, IT IS WORTH IT!
With plants only your pond will get rather rank without some type of water circulation.
{{gwi:188246}}

Amen! Preach it PonderPaul! It can be a lot of work but it is oh so satisfying!

Oh....and to answer the op's question. You can conceivably have a nice, clear water pond with fish and no cleaning if the pond is all in balance. i.e. enough shade, not too much nitrogen, phosphates etc. But as a still very green(literally and figuratively) ponder I am still trying to figure all that out. I know some of the seasoned ponders on here can make it happen but so far, I am relying on pumps, a fantastic filter and frequent vacuuming to keep my pond looking nice. No maintenance??? Not even close!!

But still an amazing hobby that will consume you much to your delight!

Jenny

If you don't have fish it will be much easier to maintain. You will still need to clean it occasionally of leaves, and decaying plant material.