Cutting back Stipa Gigantea

I begin cutting down all our herbaceus grasses (ie the non evergreen ones) in November and continue doing it through out the winter, aiming to finish by February when the first shoots of the year begin to appear. So any time when the plant is dormant is the right time.

Thinking about it, your clump is probably in need of splitting and replanting with some fertiliser under it. This is done in spring when the new roots are beginning to grow.

I think it definitely needs splitting. You will get a lot of plants out of one that size!!! Lovely grass it is too.

Thanks owdboggy - this stipa is evergreen - at least the clump just sits there all year. Do I cut back now and then divide in spring?, or not cut back if I'm going to divide?

Then I am not sure that it is Stipa gigantea. That is definitely a deciduous grass. It dies back to straw like leaves in a clump in November.
The large evergreen grass is Pampas grass (Cortaderia sp.). That is more difficult to deal with.

It's definitely Stipa G - I have the original label! The leaves do go browny, but the clump stays the same size.

Ah, right, then first job when it has finished for this year is to clear away all the old growth altogether. And I mean down to ground level. It is the accumulated old growth which is not helping your plant. Interesting thing about all grasses is that they grow from the base of the plants rather than the top. This is why you can keep on cutting a lawn without killing the grass. When I have finished clearing up our grasses there is nought to be seen but the bare soil and perhaps a few tiny green shoots if it is later in the season and the tips of the old shoots here they emerge from the soil.

I would only add that established grasses die out in the center, so when you divide just use the outer vigorous portions for replanting and discard the rest. I would also say most grasses are best left for winter interest and cut back in late Feb to early March.

Seed heads on grasses through the winter are very attractive and good for birds. Dig it out in the Spring chop into pieces and replant what you want.

Many thanks everyone for all your help - it's very much appreciated!