Move your hosta bed.....killing the tree is not an option.

Pots.

-Babka

I would move the bed if that is possible. It's never going to get better, but only worse. You can try planting in spin out bags.

we may have discussed this once or twice.. lol .. ken

http://www.gardenweb.com/gardenweb/query/maple-roots/topic=hosta

http://www.gardenweb.com/gardenweb/query/tree-roots/topic=hosta

I've seen people use pots successfully with them. My front bed is now very difficult to work in since a red maple in the front yard has spread its roots into that bed over the years. The bed is about 20-25 feet from the tree trunk. We have given up planting there since the roots are impossible to work around even with a special shovel that has large teeth called the Root Assassin shovel--it works in other areas of the yard but it was defeated by the maple roots!

As Babka mentioned, you can use pots and bury them into the soil. But you have to remember to actually turn the pot a couple of times during the season to break the roots that are entering via the drainage holes.

I currently have a few pots that are buried. Along with turning the pot, you would need to water more frequently. You may be interested in reading my post. It's about the Fragrant Blue hosta pot that I had buried and never turned for a couple of years.

http://forums.gardenweb.com/discussions/3918002/im-a-bad-hosta-momma-fragrant-blue?n=20

Pots. You can't fight maple roots. If you water and feed in an attempt to give the hostas an advantage, the roots suck up everything you give them. Anything you plant in any remotely close area to maple trees will be consumed by the tree roots. Make sure that plants in pots have some kind of distance from the ground. If the maple roots can grow into the pot, they will. They are relentless, as tree roots should be. Trees are awesome, we need them, and if you want other plants, you need to plan how to grow them without the trees eating them.

I have no long term experience with these, but I re-planted 3 hostas and a coupl of Japanese Painted Ferns this year in spin-out bags under some Arborvitea. The beauty of the spin-out bags is that you don't have to turn them -which is easily forgotten- and so far all the transplanted specimens have done much better that they did last year.

Pieter