It is generally not the best idea to cut them down until late winter or early spring....the old blades help keep excess moisture (from snow and ice) from reaching/parking on the root ball.

I wait until I see new grass in the spring...

Most deciduous ornamental grasses can be cut back in late fall, just as one would do with end of season perennials. The convention is to leave them up through winter as they provide interest and food/shelter for wildlife but there is no "rule" that says this must be done. As long as they are sufficiently hardy for your area, the above ground foliage provides minimal additional winter protection. If hardiness is questionable, mulching just like you would do with any other perennial will suffice. This is a pretty common practice with many commercial plantings of OG's - depending on the species and exposure, many become very messy with winter winds and weather and start to break apart anyway. Early shearing or cutting back is just a way of keeping things tidy and preventing stems, etc. from dispersing all over parking lots, etc.

I've cut back lots of ornamental grasses at almost every time of year without issues. As mentioned, it can be a cosmetic decision.

I prefer the look of winter grasses uncut, but I've been through enough storms to know what a mess they can be if left to nature's doing.

Guys, we are in cold/wet winter zones...which can be hard on ornamental grasses...

Maybe your zone 8 doesn't have to worry....

We (cold zoners) actually do have a reason for not cutting them back too early...

My comments were not restricted to zone 8. There is no significant cultural reason that you must wait until spring to cut back ornamental grasses. Cold is not an issue, if the grasses are fully hardy for your zone. And I'd bet good money that my PNW winter is a good bit wetter than yours......like 3 times wetter :-) Heck, we had nearly 13 inches of rain in just November last year, a bit more than you get on average for the full 6 months of winter.

After reviewing my notes from the classes conducted by our local extension office, I am going to stand by my recommendation for leaving the foliage until spring....

No offense gardengal....but a wet freeze on our ornamental grasses (fully hardy or not) can do some damage...I have actually seen the results...nothing but spongy mush. It is even advised to leave the lawn a bit high....
We also get amazing amounts of freeze/thaw action and extended warm periods followed by negative degree temps (in less than 24 hours) which is very difficult for gardeners...probably the most challenging of any other areas...entirely unpredictable and disheartening at times.

When something is fully hardy, it is implied that its natural state be observed.

Why don't you wait? Grass isn't going to fill a hole very good or very long term anyway. Wouldn't hard fill be better?

The typical Maiden grass (Gracillimus) is pretty hardy if already well established.

Maybe you could leave two feet high of grass for winter protection, and remove the rest.

Yes sandy that is true and just like any gardener I've changed what I want to do anyway. What I forgot to mention is that I live in a condo and getting rid of excess plant material can be kind of a pain plus I've been reading more and more about layer gardening and I would like to use the grasses for this. My only access to green materials, since all are grass died this year, are the plants that I'm going to be getting rid of for the winter and the grasses would provide the bulk of it. I have access to a great hedge trimmer so I won't have any problem cutting them into small pieces and they could be left on top of my beds to decompose over the winter. I have raised beds that I've filled with a decent topsoil but the soil is still crying for more organic material. So after reading all these great post I think I'm going to do like Noki suggest and just cut them way back toward the end of Nov. Hopefully they'll make it through the winter and next year I'll have a bigger compost area available so I won't have to worry about this problem come next fall.

Strouper

I have had my pink pampas for 3 years now, and I have always cut mine down in Feb. My plant people tell me that is the time to do it. It has always started the new green leaves soon.

I have been reading all of the comments and now I'm even more confused. I have beautiful zebra grass, that a few years ago, I decided to leave up for the winter. The grass turned brown and died, so I cut it down very low to the ground. Fortunately, it has grown back after 2 years and is now very healthy. I don't want to make the same mistake this year, of not cutting it back or down and dying. I'm in zone 4 with harsh winters and just recently, we've had some heavy rain and cooler temperatures and my zebra grass is drooping badly. Cosmetically, it looks a mess. If I were to trim it back to about 1 foot, would I damage it? Or would it be better to tie it up until late winter or early spring? Thanks in advance.

By "zebra grass" do you mean Miscanthus sinensis 'Zebrinus' or one of the similar horizontally banded cultivars? If so, this is only listed to a hardiness rating of zone 5 so I am surprised yours has persisted for so long.

This is a warm season grass that goes dormant in fall after producing seedheads. All the top growth dies over winter and is routinely cut back each season to almost ground level to clear away the dead growth before the emergence of the new fresh growth in late spring. Once the top portion of the grass turns tan/brown and begins to look like straw, it can be cut back at any time.

Yes it is Miscanthus sinensis 'Zebrinus' and thank you. It has turned to seedheads, so now I'll cut it back. Again thanks for the information,

Production of seedheads is not the same as the grass dying back for the season. You want to wait until the entire plant has turned that tannish straw color before cutting back, otherwise the plant is still in active growth and will begin to push new blades, just like lawn grasses do.

When a grass develops seed heads (actually its blooming) it is at its ornamental peak, cutting it down then would be the equivalent of cutting a perennial down just when it reaches full bloom.

In fall and winter, ornamental grasses are considered show stoppers for color and texture much more so than in spring or summer when they tend to blend in as monochromatic green. In winter they make a nice contrast with evergreen plants, dormant bare stem plants, winter berries and the seed heads of other plants giving 4 seasons of interest. Usually people desire and wait for the seeds because of how they catch the sunlight rather than thinking of it as needing to be cut back because its gone to seed heads. Ornamental grass sales peak in fall at most nursery's because thats when they are so striking.

Check out the Denver Botanical Ornamental Grass Garden. People visit it in fall and winter to see the grasses at their peak performance, seed heads glowing in the sun and when they separate into subtle colors.

Snow looks fabulous on uncut grasses in winter too. The best time to cut back is late winter or early spring before new growth starts for ornamental reasons and the health of the plant.