New Alpine Bed?

So I have recently done some work to my garden.
Added the raised bed in front of the greenhouse.
And widened the patio, and built the sleeper retaining wall.

The garden slopes from left to right. As a result of this, there is a gap behind the sleepers. Sleepers level with the grass on the left to asbout 15 cm on the right.
It's bugging me

I thought of somehow building it up to the same level. But that will take a lot of soil, and I will also have to relay the grass.

I then had an idea that I really liked. Make an alpine bed/rockery behind the retaining wall. Only about 30 - 45 cm wide, but along the entire length.
And I would grow only really small/low growing plants. So wouldn't obstruct the view.

Was discussing with a friend of mine and he doesn't think it's a good idea. He says the garden is tropical. And the alpine bed wil look out of place. And that I am trying to do too much with the garden.

Thoughts??

 

Thoughts? !! I think your friend might be a bit jealous of your garden. Brilliant idea to grow lots of lovely (tropical looking) succulents along there - mixed in with a few low growing grasses...
.. So many plants to choose from

 

No, I don't think so.
He's a very good friend of mine. Has a very good "eye" for this sort of thing.

 

Maybe you would be best guided by him then

 

Sirius, a great idea!
Are you thinking of low but cascading plants like helianthemum, aubretia, alyssum, arabis etc., that would flow over the wall?
Or are you thinking tiny gem-like alpines...."cushion" type?
There are spreading very low types like sedums.....?

If mine, grasses like festucas and stipa tennuisima would feature; carex buchanii and comans bronze too; evergreens like red, orange, yellow heucheras; dwarf agapanthus like Golden Drop; libertia taupo, campanulas like Dicksons Gold and the carpatica types which form low compact mounds, mesembryanthemums that will fall over the wall, lewisias, eucomis sparkling burgandy for an exotic look, blue linum perenne, sisyrinchium May Snow/ alba ((non seeding, absolutely stunning white flowered form), scabious pink mist and butterfly blue, iris pallida variegata (grown simply for its architectural green and white foliage), eryngiums, penstemons like Huskers Red for its maroon foliage and compact habit, compact hardy geraniums like Black Beauty....this has almost black foliage, a neat cushion shape and gentian blue flowers .....and consider some of the pinks....superb glaucous foliage and scented flowers from white through to purple
I would also plunge a couple of echevarias and aeoniums in pots there.
You could have a very beautiful border there Sirius

 

Yes, I was thinking of something along these lines

 

Sirius, having a scree there for those "gem" alpines would look good.
There is a thread here about alpines where pictures are often posted.....kindredspirit grows them and shows them in a fascinating thread
I would get a basic selection, a decent book on alpines and prepare that border for maximum drainage.
Many true alpines do not enjoy wet winters so that needs to be considered.
A compromise, as outlined in my previous post, may be an option too