Hollywood Juniper

91120Ah, something vintage! Remember Hollywood juniper, Juniperus chinensis ‘Kaizuka’ (or ‘Torulosa’) flanking big two-car garage doors of mid century modern homes? Those that are still around after half a century are big and strikingly sculptural, like miniature Monterey cypress for home gardens. They get about fifteen feet tall and ten feet wide, but have potential to get significantly larger.

Hollywood juniper is an old classic that is still reasonably available in some nurseries. Their densely foliated stems twist and turn picturesquely upward, typically leaning one way or another toward sunlight or away from prevailing wind. Some say they look like frozen green flames. Their gnarly trunks and flaking bark can be exposed as they grow tall enough for low growth to be pruned away.

Because of their very irregular branch structure, Hollywood juniper is more adaptable to free-formed pruning than the presently trendy junipers with strictly upright or conical form. They must never be shorn, but do not mind if obtrusive limbs get pruned back to the main trunks. Therefore, they are actually more adaptable to smaller modern gardens than some modern cultivars of juniper are.

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Leyland Cypress

91113The ‘X’ preceding its Latin name ‘X Cupressocyparis leylanii‘ designates Leyland cypress as a hybrid of two distinct genera, namely Monterey cypress and Nootka cypress. (Those who consider the parents to be two species of the same genus know Leyland cypress as Cupressus X leylandii.) The many cultivars combine desirable qualities of both parents, but also innate weaknesses.

Rows of Leyland cypress grow fast to become densely evergreen windbreaks or informal screens within only a few years. However, they are very susceptible to cypress canker, and are likely to succumb within twenty five years or so. Farther inland, they may not last half as long. That may be quite acceptable for temporary windbreaks in front of slower but more permanent shrubby trees.

Common Leyland cypress develops a distinctly plump but conical form, with slightly grayish foliage. Most other cultivars are more columnar. Foliar color ranges from bluish green to gold. The tiny scale leaves are densely set in flat sprays. Healthy trees can get nearly thirty feet tall in ten years. Most stay lower where exposed. Crowded trees that live long enough exceed a hundred feet tall.

Weeping White Spruce

41029As the colorful deciduous trees go bare, the evergreen trees get more attention. A weeping white spruce, Picea glauca ‘Pendula’, really stands out. It grows slowly to only about fifteen feet tall and maybe five feet wide, so does not need as much space as a typical spruce tree. What makes it so distinctive is the weirdly pendulous stems that hang limply from a strictly vertical trunk. It is hard to believe that it is only a different variety of the same species as the dwarf Alberta spruce, which is very short, dense and symmetrically conical, with stout little stems. The foliage of weeping white spruce is lighter green than that of most other spruces, but is not as blue as that of blue spruce. The short and stiff needles are rather prickly to handle.

The narrow and weirdly sculptural form of the weeping white spruce is no good as a shade tree, but is an excellent trophy tree for a prominent spot. Full sun is best. A bit of shade can cause the main trunk to lean toward sunlight. Young trees should only be staked if they need it, since they can become dependent on stakes. The lowest limbs can be allowed to creep over the ground.

Hedges – Living In The Background

90918thumbPretty soon, as autumn weather starts to get cooler, some deciduous plants will develop brilliant color before defoliating for their winter dormancy. Throughout the rest of the year, evergreen plants with gold, silver, bronze, bluish, purplish, reddish or variegated foliage are more colorful than common green foliage is. A few deciduous plants with colored foliage turn different colors in autumn.

Such colorful foliage is generally appealing in the garden. However, there are reasons why not all plants in the garden are so colorful. There really is the potential for too much of a good thing. If all foliage was always colorful, landscapes would look cluttered. Flowers would not be so prominent. There are many situations for which plain and simple evergreen foliage is likely the best choice.

That is why simple evergreen hedges of the various species and cultivars of pittosporum, privet, holly, arborvitae and laurel are still so popular. Some are formally shorn. Where space is sufficient, others are informal screens in which the shrubbery is more or less allowed to assume its natural form and size. The various boxwoods are useful for smaller evergreen and formally shorn hedges.

Most contiguous hedges and screens are intended to separate spaces or obscure fences or buildings. Some sporadic sorts might only expected to disrupt the expansiveness of large buildings or partially deflect prevalent breezes. What they have in common, is that they are in the background. Some are behind or next to lawns, patios or decks. Others are behind more prominent plants.

Shearing hedges that are adjacent to lawns, patios and decks is of course much easier than shearing those that are behind other plants. Screens or hedges behind rose gardens, dahlias, flower beds, or anything that might be damaged by the process of shearing a hedge, should be of the sort that do not need to be shorn regularly. Nor should they be so colorful that they steal the show.

If possible, maintenance of hedges should be scheduled to coincide with the off season of plants in their foreground.

Fake Six on Saturday

P90824K‘Six on Saturday’ is a weekly tradition for many of us who enjoy sharing six horticulturally oriented pictures on Saturday. I just did it earlier this morning.

This is not ‘Six on Saturday’. It is just one picture of six arborvitae. What’s worse is that there is an indistinguishable seventh at the far end of the row. It blends into the sixth in this picture. There are seven barberry between them, with the seventh beyond the last arborvitae. This picture was taken more than a week ago, so most of the amaryllis are done blooming now.

This row of arborvitae and barberry was installed early last winter, after a grungy hedge of photinia was removed. It would have been nice to salvage the photinia, but they were such a mess that the process would have taken more than two years, and even then, would have been patchy.

These arborvitaes will not grow into a contiguous hedge like the photinia were, but already soften the otherwise uninviting visual impact of the plain and uniform fence behind. They will grow taller and broader, but will never get so big that they will be difficult to maintain. It should be easy enough to get behind them to prune away parts that get too close to the fence.

I happen to be pleased that we were able to incorporate this sort of formality into an otherwise completely informal landscape. The irregularity of the terrain, as well as the randomness of the big forest trees that were here before landscapes were installed, make such formality nearly impossible. Even if it were easier, formality is not exactly fashionable in landscape design.

Despite their imposed formality and exotic origins, both the arborvitae and the barberry are remarkably compatible with the native flora of the surrounding forest landscape.

Oriental Spruce

60127If it got as big as it does in the wild, Oriental spruce, Picea orientalis, would not fit into many home gardens. It can get more than a hundred feet tall! Fortunately, it does not often get much more than twenty five feet tall locally. Trees that compete with taller trees in forested landscapes might get to forty feet tall. Their symmetrically conical canopies get about fifteen or twenty feet broad.

The tiny needles of Oriental spruce are less than half an inch long, so are smaller than those of any other spruce. Relative to the finely textured deep green foliage, the densely arranged and neatly angular stems are notably stout. Like other spruces, Oriental spruce is best where it has sufficient space to retain lower stems down to the ground. It can look rather silly with a bare lower trunk.

Garden varieties are more common and stay smaller than the straight species. ‘Skylands’ has yellow foliage, although it fades in warm situations. ‘Aurea’ has paler pastel yellow new foliage that matures to green. ‘Gowdy’ has a narrow columnar form, and grows very slowly. ‘Nana’ develops as a plump low mound that stays less than three feet tall. All like to be watered somewhat regularly.

Conifers Have A Woodsy Style

81205Conifers are the most prominent forest trees in North America, but are notably scarce in home gardens. Except for compact varieties of juniper (which were probably too common years ago) and arborvitae, most conifers are trees that get too big for residential gardens, and few adapt to regular pruning that might keep them contained. Almost all are evergreen, so block sunlight in winter.

Gingko (maidenhair tree), bald cypress and dawn redwood happen to be deciduous conifers; but gingko is typically thought of as a ‘broadleaf’ (not coniferous) tree, and bald cypress and dawn redwood are quite rare. The various podocarpuses are useful coniferous trees that happen to be very complaisant to pruning, but like gingko, they are typically thought of as broadleaf trees.

Junipers and arborvitaes are just as practical for home gardens as they ever were, and the many modern varieties that have been introduces over the years are even more interesting than the old classics. Modern arborvitaes are more compact. Modern junipers exhibit more colorful foliage, and more distinctive forms and textures. Foliage can be lemony yellow or blue like a blue spruce.

Simply speaking, conifers are cone bearing plants. They are typically outfitted with needle or scale leaves. Of course, it is not that simple. Juniper seeds are contained in fleshy structures that resemble berries. Gingo and podocarpus seeds actually come with a squishy mess. So, ‘cones’ are not always as easy to recognize as pine cones are. Neither are the wide ‘needles’ of gingko.

Redwoods, pines, cedars, cypresses, Leyland cypresses, spruces and firs are the more familiar of the larger coniferous trees. Bunya bunya, Norfolk Island pine, western red cedar, incense cedar and the various yews and chamaecyparises are somewhat rare. Larch and hemlock are very rare because they do not like the climate here. With few exceptions, these larger conifers have dominant central trunks that can not be pruned down without ruining the structure of the trees as they develop.80516

‘Red Star’ Atlantic Whitecedar

60106Is it red or white? Actually, it is neither. ‘Whitecedar’ is the common name for Chamaecyparis thyoides, which is a formidable coastal conifer from Maine to Mississippi. ‘Red Star’ is a much smaller garden variety. Its finely textured foliage is bluish green when it first emerges in spring, and can turn slightly purplish or bronzed gray if it gets cold enough in winter, but never turns red.

In more humid climates, ‘Red Star’ Atlantic whitecedar can eventually reach second story eaves, and can get half as broad. It rarely gets half as large locally, and can take quite a few years to do so. The slightly aromatic evergreen growth is densely conical, almost like a lumpy dwarf Alberta Spruce with an upwardly rounded underside. It can be a bit more sculptural if partially shaded.

Even without pruning, ‘Red Star’ Atlantic whitecedar is symmetrical enough for formal landscapes. Alternatively, it can add a bit of formality to relaxed landscapes. Although it is slow to provide privacy, it works nicely as an unshorn hedge. If somewhat crowded in a row, it grows taller faster. Shorn hedges lack natural form, but can recover their natural texture between shearing.

Boulevard Cypress

51230Between New England and the Pacific Northwest, the boulevard cypress, Chamaecyparis pisifera ‘Cyano-viridis’, is classified as a small tree, even though it gets no bigger than large shrubbery. Locally, only very mature specimens reach the eaves, without getting much more than half as broad. Trunks and limbs remain concealed by fluffy evergreen foliage. Warm and dry air limit growth.

The handsome foliage is strikingly silvery blue, comparable to that of Colorado blue spruce or blue Arizona cypress, but with a surprisingly soft texture. It is really quite distinct from other evergreens, even other closely related chamaecyparis.

Boulevard cypress prefers cooler climates, so does well locally in light shade sheltered from wind. During warm weather, it can get roasted if too exposed. Although it does not require much water when mature, it is happiest if watered somewhat regularly.

Living Christmas Trees Grow Up

81031All around town, there are Italian stone pines, Canary Island pines, Monterey pines and Aleppo pines that are much too big for the home gardens that they live in. Some are too close to pavement or foundations. Others are under utility cables. Many are shading or crowding out other more desirable plants. What most have in common is that they started out as living Christmas trees.

Because they seem to be so cute and innocent when they are decorated in a small pot, living Christmas trees very often get planted where they really do not belong. Not much consideration is given to their true potential. Pines are innately difficult to contain, and can not easily be pruned back for confinement once they get growing in a space that is not spacious enough for them.

Living Christmas trees simply are not often the horticulturally responsible option for Christmas trees that we would like to believe that they are. Very few end up in good situations where they have room to grow. Planting them in the wild is not practical, since their roots are too confined to survive without watering. Because they are not native, they should not be planted in the wild anyway.

Contrary to popular belief, the most popular of the living Christmas trees do not do well in containers long enough to function as Christmas trees for more than just a few years. Some spruces and small pines can be happy in containers for many years, but can be demanding. If their roots get too disfigured, they are less likely to adapt to the landscape when they outgrow containment.

Ironically, cut Christmas trees are usually more practical than living Christmas trees. They may seem to be expensive, but they are less expensive than living Christmas trees of good quality (unless a living Christmas tree functions for a few years.) Even though they are bigger, cut Christmas trees are not as heavy and unwieldy as the big tubs of soil needed to sustain living trees.

Cut Christmas trees are not harvested from forests, but are grown on farms like any other horticultural commodity. There should be no guilt associated with bringing one into the home. In the end, they can be composted or otherwise recycled like green-waste. There is no long term commitment, and no need to provide accommodations for an eventually humongous tree in the garden.

Those who insist on procuring a living Christmas tree should choose responsibly, and be ready to accommodate a growing young tree. Although not big enough to be real Christmas trees, dwarf Alberta spruce like those in the picture above are sometimes decorated as a small live Christmas tree. They happen to be conducive to confinement in proportionate pots. One in the ground, they grow like strictly conical shrubs that do not get big enough to cause problems.