Plants for shallow bed with rock, concrete beneath …

Hi and happy spring to you all !
I have a flower bed around the head of a stream that is piped beneath my garden. There is about 8 - 10 inches of soil before hitting rock/concrete supporting the pipe work. I’m looking for ideas for something that is shallow rooted, evergreen and high/wide enough to obscure the concrete surround above the stream “tunnel”. I did have a potentilla in that spot but it didn’t grow high or wide enough for the job… any suggestions ?
Tia

 

Hi @glosmike

How sunny/shaded is the area?

If it is sunny, two plants I thought of are hylotelephium (sedum) and lavender. Though hylotelephium are not evergreen, I have found that the period during which they are inactive is quite short. Lavender is evergreen.

For shade, ferns, some of which are evergreen.

 

Thank you Costask.yes it is sunny so I’ll have a look at your suggestions !

 

No problem @glosmike

In that case I would lean towards "Mediterranean style plants" - but you will need to make sure you don't overwater, as drainage will be an issue due to the concrete. I would certainly start with lavender, maybe add some smaller grasses etc. You could also add some rocks if you like that style.

 

Grasses have roots that matter only in the first 10 inches usually. Many ornamental grasses.

Yarrow is quite drought hardy and also spreads by rhizomes, there are flowers of all colours except blue, and you can buy seed for cheap, eg. Search
Its not very tall though

Elder is pretty tough, handles a bit of drought and likes moisture. generally any bush with restricted root space will stay small though

You could do a clumping bamboo

 

Ok thank you Adam !