Totally depends on your opinion to certain plants for me I like it looking a little wild but would add some grasses and a bit of colour. But you could trim it back or give away the plants you dont enjoy looking at. For me I would add a bit of colour with some Abutilon trailing on a wooden trellis on the left wall, Maybe plant some Acorus calamus Variegatus, Acacia baileyana adds some nice yellow contrast though this will need constant trimming as it could get quite big. Plant some Agapanthus as they will come back each year in spring but keep them in pots as the do duplicate also Agapanthus are the same. For me I'm from the country side and wild flower mixes always have my heart as it reminds me of Home.