Hortus murus
The hortus murus or 'living wall' will be composed of Thuja plicata, 'Western Arborvitae.' This species, native to the Pacific Northwest, is much less palatable to deer than its cousin Thuja occidentalis native to Maine.
Left to grow as a solitary specimen, it can range up to 150 to 230 feet. However, it reaches more modest heights when planted as a hedgerow.
It tolerates partial shade and grows well in Maine's climate zone (5).
Arborvitae is Latin for 'Tree of Life.'
Pentagon
Designing the hortus murus as a pentagon, the trees would be spaced 5' from each other. Every wall would have two ranks of trees, an inner rank of 6 trees and an outer rank of 5 trees. A gateway through one of the sides would be created by removing the trees indicated in shades of blue. Each of the sides of the pentagon is parallel to one of the sides of the enclosed decagon.
Golden Spiral
It would also be possible to design the hortus murus as a golden spiral. In the abstract, this is a better design; it would flow like dancers moving together, the spiral holding the cross and benches the way dancers do their partners, with the left arm extended and the right curled around their partners' backs. However, in reality, this design might leave the meditators in the garden feeling that the western side was too open and the northern side too cramped.
In this design, there would be different numbers of trees on the sides (from 7 to 19) with different spacings between the trees (from 4' to 5' 8").
Boxwood
Yew
Spruce
Arborvitae
Although western arborvitae is our tentative first choice, there are alternatives with different trade-offs. Boxwood would be more shade-tolerant but only grows to ~ 3' high. Yew is also shade-tolerant, grows to ~11', but deer think it is delicious. White spruce is shade tolerant, deer resistant, grows to ~50', native to coastal Maine, readily available, but not often used in hedges. Western arborvitae tolerates partial shade, grows to ~13' in a hedge, and is deer resistant. I think we should start by trying it first and see whether it will tolerate the shade of the meditation garden site.