Perennials like Geranium Rozanne?

[Porridgeislife]

We have inherited a large, south facing mature tiered garden. Most of it is planted with specimen shrubs like hebes, euonymus, beech, cypress and various alpine plants. We are on flinty clay.

It feels a bit municipal and I have been slowly softening it up with nepeta, hardy geraniums and perovskia. Lavender, ferns and stonecrop also do well.

We have an odd bare area of 3x3m that I need to finish planting up this year.

What else can I plant that is slug proof, not needy, flowers freely and ideally forms a spreading mat like Geranium Rozanne?

Campanula
Phlox
Almeria
Deadnettle
Creeping thyme

Persicaria forms a great mat, lovely flowers too.

Pulmonaria
Scabiosa
Erigeron
Forget-Me-Not
Aquilegia
Muscari
Poppies

Rozanne for me is pretty big so I am thinking veronicas (blue or white, blue ones age more gracefully IMO) yellow loosestrife (spreads very enthusiastically) astrantia (white, pink, dark pink) - nice big clumps or of course one of the 100s of other hardy geraniums. All of these thrive in my garden - which is on clay and unquestionably the slug capital of England.

Phlomis is quite impressive - I love mine and it really spreads!
agapanthus - beautiful
I also like epimedium but the flowers are quite small.
japanese anemones

I would think about how tall you want the planting to be. I’ve just yanked out armfuls of Roxanne because it’s swamped everything else!
I would go for astrantia, verbena bonariasis at the back, creeping phlox, pinks and cyclamen at the front. Perhaps some shrub roses?

Achilles Ptarmica are good -about 18inches tall - bright white small flowers

Russian sage
Japanese anemones
Curry plant
Woodruff

Agapanthus is a good shout.

Thanks everyone! Achilles Ptarmica and Phlomis look good.

This is the area I’m trying to fill. I have another Russian Sage to move in front of the cordyline so it’s the area at the very back and right hand side I need to fill. Low green plant on the left is sedum, probably lime sparkler.

Ohh yes a rose! I’ve always loved this one
https://www.davidaustinroses.co.uk/products/tottering-by-gently or this one:
https://www.roses.co.uk/product/531113/rose-simple-peach-3l-4l-potted

Dianthus.

Penstemon. Geranium elke is well behaved for me, maybe some tiarella, ajuga though it can get a bit out of hand. Erysium Bowles mauve.

Salvia; delphinium or slug-free aconite; veronicastrum; wallflower; silene diocia/vulgaris; primrose; rudbeckia; cephalaria gigantea; echinops; eryngium should all do well as they're easy growers.

Astilbes and Salvias

I agree with dianthus. A lot of mine are evergreen and the foliage lasts through the winter. Some geums would look nice there too.