It’s a matter of personal choice whether you cut back your ornamental grasses in fall or spring. Most ornamental grasses will remain attractive if left standing throughout the better part of the winter. They may even provide food for the birds. However they may also provide shelter for mice and voles.
If you do choose to leave your ornamental grasses standing, you will want to cut them back by early spring, before the new growth begins to grow into the old blades and makes it impossible not to cut back both.
The more full and beautiful an ornamental grass is, the messier it is when cut down. To lessen the mess of long grass blades spilling throughout your garden, use this quick and easy technique for cutting back ornamental grasses.
Wrap tape around the circumference of the grass. Any wide tape will do, as long as it’s sticky enough to keep a hold on the grass blades. A strong masking tape is preferable if you plan to compost the grass.
Depending on the width and height of the ornamental grass, you may need to wrap tape in 2-3 positions along the height of the grass and possibly divide the grass blades into 2-3 bundles. The grass shown here is relatively young and can be bunched whole.
If your ornamental grass is well established, you may prefer to use a power hedge trimmer to do the job. Either way, pre-bundling the grass will make it an easier job than grabbing handfuls of grass blades and hand pruning.
Information supplied By Marie Iannotti, About.com Guide