When I went over to see just which plant you were asking about, I encountered the gardener for that area.  “I know just which plant you’re talking about,” she exclaimed before I had finished reading her your first sentence.  “That’s such an exciting plant!  I love it, too.”

It’s Coprosma, an Australian native, and ours is a gorgeous variety called ‘Evening Glow’.  It’s a slow grower and ours looks so full because the gardener combined six plants from 4-inch pots into that container, and they have grown this well in two years.  We don’t know how much pruning this will need over time, as a few shoots are already starting to come in solid green, which is pretty but not nearly as dramatic as that gorgeous variegated foliage.  Although it displays this variegation all the time, the color will get a little more coppery during our autumn months.  Unfortunately, it’s not hardy here. 

Here's some additional information on this plant from The National Gardening Association.  https://garden.org/plants/view/118534/Australian-Mirror-Bush-Coprosma-Evening-Glow/.

Courtesy of NYBG Plant Information