One thing to remember about 'grasses' - they are divided into sedges, which do much better in damper, heavier soil, and will tolerate some shade; true grasses, which like full sun and free draining soil; and rushes, which like really damp or wet situations.

So it depends on the conditions you're wanting to plant into which would be a better choice. You've already said the soil is heavy with some sun, but if the area is in full sun, you could work in plenty of grit prior to planting if you want actual grasses, to help with drainage. With regard to Sedges, Carex seem to tolerate some dry quite well, and many are evergreen. Carex 'Evergold' is a good little workhorse - evergreen, doesn't seem to mind drier conditions and quite a lot of sun. That's the other thing about grasses - many disappear in winter, aren't hardy (some of the Pennesitums particularly) or turn into a pile of dead looking strands - even so, Hakonlechloa 'aureola', the Japanese Fountain Grass, is a thing of beauty during the growing season - it does not like really dry conditions, but can't stand being waterlogged either - prefers a bit of shade, but I grow it very successfully on a full sun balcony here, though I notice the colour is more faded in full sun. I only mention it because its one of my favourites!

Some information about Miscanthus (one of the taller types of grass) here

http://www.saga.co.uk/magazine/home-garden/gardening/advice-tips/winter-garden/tall-grasses-for-winter#

and more general info about ornamental grasses here

https://www.rhs.org.uk/advice/profile?PID=140

Just a warning: if you go for Carex - don't get Carex pendula. Got rid about four years ago and still digging up seedlings from everywhere...

Blimey, Stera, didn't realise people actually bought it - I find it pops up in gardens all on its own, and if you don't recognise it early, its a pig to get out... but a good warning, in the circumstances!

I was warned not to plant it but didn't listen because I loved the way it bends over at the top and looks so dainty.
It took a lot of digging out too. I didn't buy it actually - the nurseryman who warned me not to have it dug one up from a crack in the paving and gave it to me...

Ha ha, that should have told you something!!

Yes, well.....I did enjoy it the first couple of years before it started trying to fill the garden...

thnx all,

let me run this past you and see if i get a response.

hakonechloa

deschampsia cespitosa

anemanthele lessoniana

once had a stipia once and that wanted to self seed everywhere

Well the Hakonlechloa, specially aureola, is one I mentioned and a favourite of mine - Anemanthele I've never grown, also known as Stipa arundinacea, does seed itself, no idea how much of a pain seedlings are, though my Grasses bible says they're not too much of an issue, sounds like a good doer. Deschampsia does best in moist soil with some sun...

cheers bamboo. you are a mine of useful info. thinking of taking out the top few inches, then grit, some ericacious and some multi purpose.
cheers pal

I wouldn't recommend that; you're best off digging over what's there, adding well composted materials (compost heap or composted animal manure or similar from the garden centre) and a bag of horticultural grit, working it all in together. Let it settle for a week and then its ready to plant.