During the Colonial Period of America, American arborvitae, Thuja occidentalis, was one of the first native species to become popular for home gardening. It is native as far south as the Great Smoky Mountains, and as far east as Minnesota. Wild trees can be fifty feet tall, with trunks as wide as three feet. They might grow larger to compete with other trees.
Of course, the oldest cultivated varieties, as well as relatively modern cultivars, are much more compact. Many modern cultivars are hybrids. Some are different species. They are densely evergreen shrubbery that work well as hedging. Their distinctly ruddy or grayish brown bark is barely visible. Their bloom is unimpressive. Foliage is their primary asset.
It is quite an asset. Although arborvitae is conducive to shearing, its billowy foliar texture is too appealing to compromise by frequent shearing. Scale leaves are barely more than an eighth of an inch long, like those of junipers, but are more pliable on soft and flattened foliar sprays. Such sprays are delightful coniferous evergreens for wreaths and garlands.
Colorado and Utah share the same stately state tree; the Colorado blue spruce, Picea pungens, which is native to the Rocky Mountains between Arizona, New Mexico and southern Idaho. Colorado blue spruce are stoutly conical trees that grow slowly to eventually get more than seventy five feet tall. Where they need to compete with other trees in forests, the biggest are nearly twice as tall with trunks nearly five feet wide. However, because they grow so slowly, and do not get much bigger then they need to, well exposed trees stay proportionate to home gardens for many decades. Many shrubby compact cultivars actually stay less than ten feet tall. Foliage can be grayish green to silvery pale blue. The stiff and sharply pointed needles are about three quarters to an inch and a quarter long, and densely set on relatively rigid stems.
The elegant silvery blue foliage of the Colorado blue spruce is striking either in front of or behind darker evergreen foliage, like that of redwoods or junipers. These stout and densely foliated trees make any garden look a bit more woodsy.
Hollywood juniper had formerly been the only popular juniper of tree form. As it became less popular during the past few decades, cultivars of the once obscure Rocky Mountain juniper, Juniperus scopulorum, became more popular. Also, a few more modern cultivars became available. Now, the once overly common Hollywood juniper is quite uncommon.
Rocky Mountain juniper is naturally rather grayish for protection from the harsh exposure of the high elevations which it inhabits. Cultivars are grayer, bluish or silvery, and mostly develop symmetrically conical form. Old specimens that were initially conical eventually grow as small trees with rounded and relatively dense canopies, perhaps on bare trunks.
‘Skyrocket’ and ‘Blue Arrow’ are very narrow like Italian cypress that grow only fifteen feet tall. ‘Wichita Blue’ and ‘Moonglow’ are stoutly conical. ‘Blue Arrow’ and ‘Wichita Blue’ are bluish green. ‘Skyrocket’ and ‘Moonglow’ are silvery gray. Established specimens do not require much water, but develop better foliar color with warmth and occasional watering.
Gardening was easier before suburban lifestyles became so passe. Now, larger modern urban homes occupy smaller urban parcels. Modern fences are taller to enhance privacy for such densely situated homes. Garden space is both minimal and shaded by so much infrastructure. Ironically, shady evergreen foliage is now more practical for such gardens.
Deciduous trees are still practical for single story suburban homes on suburban parcels. They provide cooling shade for summer, and allow warming sunshine through for winter. Smaller evergreen trees and shrubs closer to fences obscure unwanted scenery beyond, without shading homes during winter. Such strategy is facilitated by sufficiency of space.
It is not so practical for confined and modern urban gardens though. Space is insufficient for big deciduous shade trees. Smaller trees can not get tall enough to shade roofs of tall modern homes. Insulation of modern homes is fortunately so efficient that summer shade and winter sunshine are not as advantageous as they still are for older suburban homes.
Therefore, most trees in modern home gardens primarily obscure unwanted scenery and provide privacy, rather than merely provide shade. Not only should they be proportionate to their gardens, but such trees should also retain evergreen foliage as low as the tops of associated fences. Some of the more practical options are actually evergreen shrubbery.
Large evergreen trees, such as Southern magnolia, California pepper, camphor, various palms and some eucalypti, are too big for some confined modern home gardens. English laurel, New Zealand tea tree, hopseed bush, various arborvitae, and particularly various pittosporum function as small evergreen trees that are proportionate to confined gardens.
As practical as evergreen foliage is for modern urban home gardens, it requires as much maintenance as other forms of vegetation. Contrary to common belief, evergreen foliage sheds. It is just sneaky about doing so slowly throughout the year. Additional foliage also innately adds shade to already shady situations, which can complicate other gardening. To become compact evergreen trees, shrubbery requires directional pruning.
It is unfortunate that most live Christmas trees grow too large for compact home gardens. Japanese black pine, Pinus thunbergii, which is very rarely available as a live Christmas tree, does not get much taller than twenty feet locally. Although it can slowly get about as broad, its sculpturesque branch structure adapts to pruning for containment if necessary.
Japanese black pine is a notably versatile pine. Most pines are excurrent (with a primary central trunk) or develop another similarly uncompromising form. Few are as cooperative with such casual form and relatively contained size as the Japanese black pine is. In the wild, it grows taller than a hundred feet. Yet, it is also very popular for bonsai and niwaki.
The evergreen foliage is richly deep green. The paired needles are about four and a half inches long, and perhaps stiffer than they appear to be. The cones are about two or three inches long, and nicely symmetrical. Fresh foliage and fresh or dried cones are useful for home decor. Even young trees have handsomely flaky bark, which darkens with rain.
Poinsettias, Christmas cacti, cyclamen, various forced bulbs and several other seasonal potted plants are again becoming popular. It happens annually prior to Christmas. Heath, heather, rosemary, English holly with berries, and delightful compact conifers have been gaining popularity for many past years. Seasonal potted plants are increasingly diverse.
Unfortunately, few survive for long after Christmas. Forced bulbs exhaust their resources. Cyclamen are likely to rot after a month or so. Very few retire to a garden. Poinsettia gets too lanky in the garden to be a favorite. Most seasonal plants simply succumb to neglect. After their primary performances, they are no longer interesting enough to justify tending.
In reality, some of these seasonal potted plants are little more than cut flowers with roots. These roots allow them to live longer than cut flowers, but their ultimate fate is the same. Wreaths, garlands and various seasonal cut greenery likewise serve a purpose, but only temporarily. Without roots, it all lacks any potential to retire into a garden after Christmas.
Christmas trees are really not much different. Although there are several different sorts of Christmas trees, they fit into similar categories as cut foliage and seasonal potted plants. Obviously, they are seasonal. They need not last much longer than Christmas. Although, some have a potential to do so, few survive or function for more than a few Christmases.
Contrary to popular belief, and their expense, cut Christmas trees are generally the most practical Christmas trees. They are essentially a very substantial sort of cut foliage. They grow on farms like any other foliage and vegetables. After such a tree serves its purpose, it resigns to compost or green waste recyclery. A freshly cut tree can replace it next year.
Large potted Christmas trees may seem to be more practical, but require maintenance to remain as appealing as they are now for another year. Despite the expense, few last that long. They want to get out of confinement, so that they can grow as trees. Pre-decorated small trees are Italian stone pines. They grow much too big for contained home gardens.
Sitka and Brewer spruce both live at low elevations and near the coast within their native ranges. Yet, neither perform as well here as blue spruce, Picea pungens, which is native to much higher inland regions of the Rocky Mountains. It grows neither as big nor as fast here as in the wild, so few old local trees are taller than thirty feet, or broader than twenty.
Although compact, blue spruce should get sufficient space to develop its densely conical form without pruning for confinement or clearance. Such pruning is disfiguring. Since the evergreen canopy is so dense, it should retain low branches to the ground for as long as possible. Blue spruce works more like big and formal shrubbery than like compact trees.
Some cultivars of blue spruce are very stout and rounded. Most have remarkably blue or silvery color. Seed grown trees (which are not cultivars) are sometimes available online. They have potential to exhibit notable variation. Some might develop slightly more open canopies, with elegantly upwardly curved limbs. Spruce needles are about an inch long with quite a prickly texture.
Of the several junipers that were too common decades ago, the golden pfitzer juniper, Juniperus X pfitzeriana ‘Area’, was the one outfitted with cheery, bright yellow new foliage each spring. Similar but more compact varieties that are more popular now were rare back then, or simply not yet invented. Contrary to the stigma, golden pfitzer juniper is a very tough shrub, which is why so many from decades ago remain in older gardens, and new plants can sometimes be found in nurseries. Once established, they need very little water, or none at all. A bit of partial shade is tolerable, but inhibits color. Angular branches radiate outward, with the finely textured foliage drooping only slightly at the tips. Mature plants get wider than six feet, and taller than four feet. Crowded plants can stand taller than six feet. Golden pfitzer juniper can technically be shorn as hedges, but are so much more appealing if selectively pruned to maintain their natural form. They are at their best where they have space to spread out naturally without pruning.
Juniper seedlings are initially outfitted with needle-like juvenile foliage. As they mature, most develop scale-like adult foliage. ‘San Jose’ juniper is the juniper that does not want to grow up. Even very old specimens exhibit odd tufts of juvenile foliage. Variegated ‘San Jose’ juniper has random cream colored blotches. The angular but sprawling stems can spread more than six feet wide without getting two feet deep.
Most shrubs and many perennials get larger than the diminutive mugo pine, Pinus mugo. The most common type grows very slowly as a dense and rounded mound only a few feet tall and maybe twice as wide. Only a very old specimen might reach an eave. The paired dark green needles are about one or two inches long. The symmetrical brown cones are a bit shorter. Mugo pine is also known as Swiss mountain pine and because of a misprint in the eighteenth century, mugho pine. Although native to mountains in Europe, mugo pine is most popular in Japanese gardens and for bonsai. Because it grows so slowly, it can be happy in planters and large pots. In large urns of regularly changed flowering annuals, it can be a nice permanent and evergreen centerpiece.