Perennial are so easy to maintain, just cut them back in Feb before any bulbs come up, otherwise just pull out any weeds you can see. Hope that's helpful.

Don't be fooled by the concept of low maintenance gardens! All gardens require some form of upkeep. From the picture I would have thought there is an awful lot more out of view so would suggest that perhaps not high maintenance, but to keep it looking good will take time, effort and of course funds!

You are so true, the client did have a gardener once a week as the rest of the garden is pretty large by most peoples standards!