Evergreen shrubs to go alongside Viburnum plicatum tomentosa Mariesii?

My lovely doublefile Viburnum are still in their infancy, and I could use some suggestions for filling out the beds with both permanent and temporary denizens.

I'd love some recommendations for harmonious, relatively low-growing shrubs to go in front of the Viburnum - there is a Physocarpus "Summer Wine" proximate, and a Nandina "Gulf Stream" on the other side, facing South with Western exposure.

Given that triumvirate, I'm also interested to hear what perennials people think might look well, again, mainly occupying space while the Viburnum grow to its full size. I have a Thalictrum Rochebrunianum I'm thinking of putting in near the Nandina, and would love to get my hands on some Penstemon "Blackbird" (why do best plant picks disappear from nursery stocks one year after they get that designation?)...

I live in Vancouver, and would really appreciate recommendations based on what might be obtainable here. Many thanks!
Boondoggle

 

Due to the tabular habit other shrubs with horizontal branching are harmonious companions. The whiteness of the floral bracts really stands out against a solid purple or dark green backdrop. A good purple Japanes maple like 'Nigrum' would have a suitable habit and coloring. Otherwise some dark green dwarf conifers, used in sufficient number and close enough together - or a sheared dark green conifer hedge - could make the viburnum show up well.