Posted: 20/10/2013 at 22:54
For now, for the winter, leave them alone.
In spring try to make a mound of soil around the grasses to make a sort of reservoir and water really well. Then, yes, mulch with something substantial like dried manure. It's funny I have a couple of miscanthus morning light....one is growing in good rich soil and is 7' plus and full dense foliage. The other is in my front garden where soil is more sandy. It is only half the size. I will move it soon.. should not really move in autumn ......but Im confident it will be ok.
Many grasses like dry conditions....stipas for example and calamagrostis and you could try them there. These flower earlier in the summer.
Good luck mowmymoss