Using Large Evergreens in the Landscape BY ANN MILOVSOROFF
Fall 2007 - Vol. 20 No.2

Large evergreens make a backbone for any planting, distinctively define spaces, and create an atmosphere or personality for a property. They are good as single specimens, superb in groups, and impressive as hedges or windbreaks. Mixing the green and blue Colorado spruces (a spruce salad), or punctuating the main species with a couple of another type and texture is a nice way to emphasize their characteristics.
Hemlocks (Tsuga canadensis) are one of the most graceful of the large evergreens. They can also be maintained as large hedges with regular pruning. Horsford’s is now growing our own hemlocks in order to be100% sure that there is no chance of introducing the wooly adelgid pest that is killing hemlocks (alt: has been contained) in southern New England. This year our trees are at the 4’ height – a nice size for being moved to new homes – and we look forward to being able to offer larger sizes in coming seasons. Hemlocks prefer a moist but well-drained soil, a somewhat sheltered situation, and at least partial sun although they ill grow, slowly, in full shade. They naturally occur on north slopes in sandier soils that have good ground water. Their shape is symmetrical but with a suggestion of the wild. “This is the forest primeval. The murmuring pine sand the hemlocks….like Druids of eld…”
Hemlock cones release their seeds intermittently through the winter, providing food as well as shelter for winter-resident birds. Summer nesters consider them very desirable real estate.
They are adorable at the 4’ size and majestic at the mature height of 60-80’. They are hardy in zone 3b and their life span can be 400-600 years. Plant now for the future!
Horsford’s has been growing arborvitaes, Thuja occidentalis, also called cedars, for years. The common name “cedar” comes from the tree’s resemblance to the cedars of Lebanon. The name arborvitae means “tree of life” and refers to the rich vitamin C content that cured Jacques Cartier’s icebound crew of scurvy, thanks to the Iroquois. Cartier took seeds back to France and they became the first recorded N. American trees planted in Europe. The arbs we sell are totally locally acclimatized, and our choice of the cultivar ‘Nigra’ results from its hardiness (zone 2) and its good dark-green winter color. Consider an arb if your space dictates a less than expansive evergreen tree, plant them in groups as if they were having a conversation, or plant them as the first choice for a medium to tall evergreen hedge or windbreak – except where there is salt spray. Cedars prefer a limestone-based soil, neutral to alkaline pH, but will grow well in both wet and dry conditions. They are a premier tree for bird and wildlife habitat and food.
White spruce (Picea glauca) is a northern native (zone 2) across the continent, and along with the Colorado blue spruce (Picea pungens ‘Glauca’), zone 3, is capable of handling wind, drought, and salt better than any other evergreen. They are also unpalatable to deer. Both have a stately conical form with symmetrical, compact, horizontal to ascending branches. Both have a bluish or glaucous coating on the new needles that fades gradually over the 7-10 year life span of a needle. The Colorado blue spruce, native in the southwestern US, has the stronger blue color. Often planted as single specimens, the white and blue spruces are perhaps better planted in groupings. They are very useful as windbreaks and high hedges.
We have some lovely Norway spruce (Picea abies) in the fields. They are now 7-8feet tall – fast-growing, not bothered by winter or summer winds, and not browsed by deer, making them a traditional choice for windbreaks. Hardy to zone 3b, Norways are big, dark green trees growing to80’ high by 30’or more wide. Their pyramidal habit, with branches distinctively curving down and then up, with branchlets hanging like graceful fringes, makes them distinguished as singles, and attaining a mythic quality in groups, groves, and lines where there is space.
On spruces the cones hang down from the branches. On firs they are upright on the branches. You can test this for yourself by planting the “Norwegian wood”, Picea abies, near an Abies concolor, a white or concolor fir. The dark green of the spruce will set off the silvery blue, glaucous color of the fir, and the hardier Norway will protect the concolor which fine in zone 4 but not happy with strong winds. Together they enliven the winter scene. Plant far enough apart so their contrasting forms converse with each other but don’t argue. The concolor firs are big teddy bear trees. They are similar to the blue spruces, being roundly compact, but with a softer, firry look – in keeping with their name – and grow to 50’ with a 30’spread. Like the blue spruce they are native to the southwest and withstand heat and cold. While they grow best on moist, well drained, gravelly or sandy loam soils they will tolerate dry, rocky areas as well as light shade. This is the best fir for landscape uses. Reportedly it has a nice citrus scent – come and sniff and report your findings.
White pines, Pinus strobus, are the quintessential Vermont tree. Hardy in zone 3 their graceful softly rounded shape – sometimes interestingly eccentric – with the soft texture of the long needles, punctuates the hardwood forests on the lower mountainsides. Lone trees on hillsides have an iconic presence. In a planting, as in the landscape, they contrast handsomely with spruces, make a fine backdrop for deciduous and flowering ornamentals, and shelter a planting of rhododendrons. Pinch the new growth candles while still soft to make young trees more compact.
Every landscape deserves at least one large evergreen, and preferably an interesting grouping or two, to offer bones to the landscape, friendship to the owners, and food and habitat to wildlife.

Tsuga canadensis - Hemlock
Horsford Gardens and Nursery

References:
Manual of Woody Landscape Plants, 5th ed.
by Michael Dirr, Stipes Publishing, 1998.
Trees in Canada by John Laird Farrar,
Fitzhenry & Whiteside, 1995.
An Eclectic Guide to Trees - east of the rockies
by Glen Blouin, Boston Mills Press, 2001.
The Urban Tree Book: An Uncommon Field
Guide for City and Town by Arthur Plotnik,