That is quite a challenge for a first garden!

The first question I would ask is - how stable are these banks in heavy weather? If the soil is going to be constantly washed downhill, it is going to complicate any plans for planting. On the other hand, if it is stable in terraces as in photos, you have great potential there.

I am sure there will be lots of good advice here if you can tell us a bit more about the soil type and which direction these banks face.

Eeek!

My first thought was, MOVE!

But I think Ojib has hit upon the positives...

You could terrace it slightly with long pieces of half log roll to form a gravel path so you can get to each bank to garden.I'll post a pic of one of my old gardens to show you what we did but thats a pretty huge expanse!! You need plants to hold the earth together and cascade down ....we used Vinca and cotoneaster and ground cover roses:-)

Thanks for that extra information in your question. That helps.

Steep, steep, steep! That is my first impression. Can you batter the slope back a bit so that it is not quite so steep? I would like to consider its potential as a wonderful rockery/scree bed but I am not sure how I would go about the construction work. If it were my garden I would try for the rockery and figure out how to do it as I went along.

Ahhh the extra information does help ...so you'll have a grass path along the flat bit ..I still think it may be wise to make a small edging on the higher slope if only because you will disturb earth as you plant .A wonderful plant for slopes is Ceanothus var repens ...evergreen and fast growing with blue flowers .It covered our slope so quickly and stopped the weeds too.Euonymus Var repens is another great plant for slopes.Or a wonderful wild flower border would look interesting but may not cement the ground enough .If it was me it would be a bank of ground cover roses with the evergreens above adding all round colour ...but thats just me:-))))Because its such an open site I dont think you'd have to worry about not enough sun but wind may be a consideration.

This is a bit like a cliff face, ok till the rains come! and I believe it can rain a lot in Ireland?
It seems to me you have remove the supporting structure to this land? so firstly I would splash out on a garden professional with local knowledge for some advice, it may be that you need to retain it first with hard landscaping to limit the risk of rain washing the bottom 2 tiers to the bottom/away, which would give the top areas nothing to sit on and perhaps putting your house at risk?

On motorway cuttings you see a mesh to stop the soil slipping, some sort of work will be needed I,m sure to make it safe

That's exactly what I was going to say, Pam, but you beat me to it. Here they have special concrete blocks that fit together to give a fairly steep but stable growing face, and plant with perennials such as ivy to give a wall of greenery. I'd possibly modify that to plant as you would a rockery so you can introduce some colour, with bulbs and alpines, small shrubs and the like.

I have been thinking about this during the day (help me, I am on holiday). The straightness of the bank is one of its problem features. As water runs off the garden above it will cause its own wash-out channels and you will have no control over it.
What I would be doing now is scalloping the edge so that I have a series of ridges and cwms along the length of the slope. These would be of different sizes and shapes to give some interest. The ridges would probably require strengthening with rock and the three walls of the cwms would be a lot shallower than the slope of the face now. Each one could then be landscaped individually if you wish and have different plantings.
I would also try to arrange some sort of drainage along the top of this slope and direct the water down deliberate watercourses in the design. Ah, I can see it coming along nicely now!

That's a great idea, Bulbaholic. Solves quite a few of the possible problems all at once and, as you say could be developed a bit at a time. Like that.

Oh yes what a good idea Bulbaholic .i hadn't thought about the huge run off its going to get .

I would love to see this interesting garden develop. Please can you post progress photos as it comes along?

You are absolutely right, Bulba. Good thinking! It came home to me the yesterday, after a water pipe in our neighbour's garden, which had cracked in the cold winter, started leaking underground, and filtered down into our garden (some 8' lower) through a stone wall. My lovely, newly planted border became a smelly quagmire and the lawn started to slide!
Ojibway's right - pictures would be very interesting to chart your progress: we all learn a lot from things like this.

hi everyone,
thank you all for your help, just being stone picking in the garden last few days 3 one tonne bags filled (hard job) have done about 1/4 of the garden (its just under 1 acre) will post photos of my work. Will take a good while for work to be done the house on it needs alot of work you can guess which gets more work done to it.
was thinking of just planting grass and do small bits at a time on the banks what do you guys think??

You certainly don't want to discourage yourself with attempting too much in one go, and that is one H**l of an undertaking you have there. If the prospect of eventually having to pull the grass out before you start proper planting isn't too depressing, it sounds quite a good idea to me. It should bind the surface fairly well once it's established. Try not to wear yourself out before you begin!