It sounds like you didn't give the Miscanthus or the Sambucus enough space, although it's likely the fence will suffer first. Recommended spacing for garden use is 60-90" for the Miscanthus and even more for the Sambucas.

On the positive side, the Elderberry will be a good visual partner with the Miscanthus. M.X Giganteus foliage fades from the bottom of the plant up, and the Elderberry will hide that from view.

Thank you Donn. These were field grown Miscanthus so I had to get them into the garden ASAP. I was hoping to screen the lower portion of the grass as you had mentioned because I had read about it looking a bit shabby by the end of the summer. After seeing some very large Sambucus nigra I should have known right away that the these two plants both need their space. There is a walkway about four feet in front of the Sambucus which is also probably asking for trouble.
The fence is chain link and although I would love to be able to hide as much of it as possible I don't intend on destroying it in the process. Time to go move some plants.

Mike