I always thought that this plant was Juniperus procumbens 'Nana,' but after a little research it looks like this plant could be J. procumbens 'Greenmound,' which is very similar to 'Nana' only brighter green and slightly more compact. Rising out from the sea of juniper are vibrant stems of the Red Twig Dogwood (Cornus alba).
The ground cover planting scheme is made up of large swaths of various evergreen plants that flow from one species to another. There are at least four different junipers, including J. horizonalitalis 'Wiltoni' (Blue Rug Juniper) as well as J. horizontalis 'Blue Chip' (it has a slightly purple tinge to its leaves). Intermixed is a lovely evergreen called Paxistima canbyi, which shows its little red stems this time of year. There is a nice visual vibrancy of the contrasting reds and greens.
I think that this is Picea abies nidiformis (Bird's Nest Spruce). It has wonderful horizontal, rounding, creeping growth that is structurally very interesting. Its form does seem to mimic a birds nest.