Hi Kizzicat, Your photo hasn't uploaded...? May need to try again.

no storage, the retaining wall didn't allow much room, and the client didn't want to go any deeper with the seat.

A lot of the time they build a core filled concrete block wall then construct another stone wall against it. The concrete block wall takes the job of retaining while the stone is for looks only. It does depend on what purpose the wall is performing. For example a retaining wall higher than 600mm (usually) needs engineering by a structural engineer which is easier to achieve with core filled concrete block on footings rather than just solid stone. You never mentioned the purpose of the wall which is a vital detail as there can be numerous ways to achieve similar outcomes.

Hi, Add some really good soil mix, a watering system would be great, I love black mondo and lambs ears together ( both very hardy) and I would plant dichondra ‘silver falls’ to trail over the retaining wall, the colours will go beautifully with the steps and compliment the house, could look gorgeous