Hebes interspersed with alliums will give structure through summer as well as attracting bees. Easy to acquire and maintain.
I've done it. Put row of lavender in and went armed to the garden centre with a list of your recommended plants but unfortunately they didn't have any so I bought Some echinacea to go at the back and some cineraria maritima 'silver dust at the front & left what was left of the irises in. It's not great but pleased it looks neat and smells nice x
Great Moomin - that's going to look gorgeous when it all gets settled - and it'll be lovely in perfect time to welcome you and your little one home