Planting in sandy ground and needing coverage

[cocopops]

Hello

It has been a while since I have been on here but I have a problem I am sure one of you can answer.

The drop from my lawn to drive is 1m in height over about 13m with an angle of about 45 degrees.  The whole of the 'soil' is very very sandy.  I have covered it with a horticultural membrane so it looks better.  I need some ideas for perennials that I can plant through the membrane and hopefully give some coverage and colour.

Any ideas?

[cocopops]

[ACE]

I expect it drains very quickly, so drought resitant plants would be best, lavenders, gaillardia, yarrow, echinacea, loads of different grasses, sea hollies, pinks and carnations. Plant in long waves and have some decorative gravel and rocks in places to fill up the gaps.