Dwarf Alberta Spruce

Dwarf Alberta spruce is densely conical.

Of all the live Christmas trees available, the dwarf Alberta spruce is perhaps the most practical. It is a shrubby little tree with a big name, Picea glauca ‘Albertiana’ ‘Conica’. (‘Albertiana’ is typically omitted.) It is a dwarf cultivar of white spruce that grows very slowly. It takes many years to potentially get eight feet tall and half as wide at the base. Wild white spruce can grow a hundred feet tall.

The main disadvantage of the dwarf Alberta spruce as a live Christmas tree is the very dense foliage. It almost seems to be artificial. The small needles are only slightly bristly, and finely textured. Otherwise, dwarf Alberta spruce can remain potted as a Christmas tree for several years. It stays sufficiently compact to return to the home annually. It just does not want to be indoors for too long.

The strictly conical form of dwarf Alberta spruce is a distinctive feature in the garden. A pair of trees elegantly flanks a doorway or walkway. A row of evenly spaced trees instills formality to a linear border of bedding plants. Although they do not get too broad, they should have enough room to grow naturally. Pruning for confinement or clearance compromises their naturally symmetrical form.

Mugo Pine

Mugo pine is more shrubby than tree like.

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.

Canary Island Pine

Canary Island pine displays fluffy foliage.

For spacious landscapes, Canary Island pine, Pinus canariensis, became more common than Monterey pine through the 1970s. New trees became less popular as old trees demonstrated how big they get! However, as seemingly docile live Christmas trees, they still often sneak into gardens that are not big enough for them. Their short blue juvenile needles suggest that they stay small.

They instead get quite tall. Old trees can get more than a hundred feet tall, even if their canopy gets no wider than twenty feet. Their rich brown bark is distinctively and coarsely textured. Their thin and long needles are somewhat pendulous, with a rather fluffy appearance. They are in bundles of three. Although individual trees are not very broad, their shade can get too dark for other plants.

Canary Island pine is a stately tree, but is not easy to accommodate. It produces copious foliar debris that can shade out lawn and ground cover, and accumulate on shrubbery. In unrefined areas, without other plants, foliar debris suppresses weeds. However, too much can be combustible. Such grand and resilient trees suit parks, and are ideal for freeway embankments and interchanges.

Arizona Cypress

Arizona cypress can be strikingly blue.

If Hetz blue juniper grew as a tree, it might look something like Arizona cypress, Cupressus arizonica. The evergreen foliage of modern cultivars is almost as blue as blue spruce. Older trees that grew from seed (not cloned) can exhibit significant genetic variability, and are more grayish green than blue. Some are stout and shrubby. Taller specimens might exhibit sculpturally irregular form.

In the wild, Arizona cypress is even more variable, with as many as five distinct varieties. Some varieties are sometimes classified as separate species. Shorter types may get no taller than a two story house. Taller types get twice as tall, and as wide as thirty feet. Trunks can get two feet wide. Smooth Arizona cypress has patches of distinctively flaking bark over shiny chestnut brown bark.

Arizona cypress are best where they can develop their natural form. They prefer no more than minor pruning of awkward stems. Although, none seem to mind grooming to eliminate dead or aging stems. Modern cultivars are more conducive to minor pruning than older trees. Some cultivars supposedly make nicely dense shorn hedges. Furthermore, shearing enhances the blue foliar color.

Bird Nest Cypress

00909
Bird nests should be so refined.

Port Orford cedar is a grand tree. It is native to the southern coast of Oregon and the very northwestern corner of California. Mature trees in the wild are more than a hundred fifty feet tall. Some of the older big trees within landscapes are more than forty feet tall. However, the cultivar known as bird nest cypress, Chamaecyparis lawsoniana ‘Nidiformis’ is remarkably diminutive and shrubby.

Bird nest cypress grows slowly, and may never get more than five feet high and wide. Individual plants are mounding with rather flat tops. A row of plants eventually becomes a low informal hedge. Distinctively flat sprays of slightly grayish evergreen foliage exhibit a soft feathery texture. Unless pruned otherwise, abundant dense foliage obscures main limbs with fissured reddish brown bark.

Most cultivars of Port Orford Cedar, including bird nest cypress, are uncommon here. They actually prefer cooler and moister climates. Locally, they are sensitive to harsh exposure and wind while the weather is warm. A bit of partial shade is no problem. Established plants do not need much water, but should not get too dry for too long. Selective pruning, not shearing, sustains natural form.

Larch

41217Climate is why the European larch, Larix decidua, is so rare here. It prefers cooler weather in both winter and summer, and more humidity. Foliage can roast if too exposed through summer. Small trees that are partly sheltered or partly shaded by larger trees have the best color and foliar density. Larch are innately reliant on somewhat regular watering, so are not drought tolerant. The mildly cool weather of autumn is enough to brown the formerly bluish foliage, which falls shortly afterward.

In the wild, larch trees can get as tall as other big coniferous trees. However, the many different garden varieties stay much smaller. Some are very pendulous. A few have contorted stems. Of the few that can sometimes be seen locally, most are compact dwarfs that grow more like low and dense shrubbery than trees. Some get only two or three feet tall and broad, and grow very slowly. These can stay in containers or planters for many years.

Not All Evergreens Are Conifers

41217thumb‘Conifer’ and ‘evergreen’ are almost synonymous. Of the two, ‘evergreen’ is the more familiar term. Some people do not know what a ‘conifer’ is. Simply speaking, an evergreen is a plant that retains foliage throughout the year, even while deciduous plants defoliate through winter. A conifer is a plant that produces seeds in cones, such as pine cones, although many are not easy to recognize as such. Actually though, not all evergreens are conifers; and not all conifers are evergreens.

Southern magnolia, glossy privet, lily of the Nile, all sorts of eucalyptus and all sorts of palms retain their foliage through winter, but none are conifers. Larch, dawn redwood and bald cypress are conifers, but are also deciduous. This can be quite a surprise for anyone expecting them to be evergreen. The foliage turns brown enough to resemble death before defoliation, although larch can get quite colorful in autumn where winters are cooler.

Now that flowers for cutting are scarce, evergreen foliage is popularly cut and brought into the home instead. Here in California, not many of us have fir or spruce out in the garden. Redwood, pine, cypress and cedar (deodar and Atlas) are more common. Leyland cypress, Western red cedar, incense cedar and the various chamaecyparis are not as common, but are just as effective. Incense cedar as well as some of the junipers (unshorn) are particularly aromatic.

Since the various hollies are uncommon here, Californians prefer other evergreens with berries, such as firethorn (pyracantha), contoneaster and toyon. Incidentally, toyon had been so recognized as a substitute for holly that it had historically been known as California holly, and is the origin of the name of Hollywood. Magnolia grenades (fruiting structures) can function like weird pine cones. Southern magnolia has big and glossy leaves with rusty orange undersides. They can provide bold color and texture, even if they have dried to a rich brown.

There are of course no rules for cut foliage. Anything that is still foliated and appealing in the garden may work nicely in the home. Ferns are an obvious choice, although some drop spores that stain fabric. Various pittosporums, podocarpus, eucalyptus, New Zealand flax and even the leaves of bird of paradise are all worth a try.

Spruced Up

P91214KSpruce happen to very compatible with the landscape style here. They fit in nicely with surrounding redwoods, but are more proportionate to sunny spots of some of the refined landscapes. We intend to add a few into some of the landscapes as they get renovated. They will stay branched to the ground, like big dense shrubbery, with the personality of distinguished forest trees.

Several dwarf Alberta spruce, which is a very compact cultivar of white spruce, have been incorporated into landscapes that were renovated during the past few years. They really are dinky though, and stay smaller than most shrubbery. Some of the very compact cultivars of blue spruce that we would like to add next will eventually get significantly bigger, but do not grow fast.

A few spruce that grow more like tree rather than shrubbery would be really excellent. The taller blue spruce with more open branch structure are no longer available from local nurseries, but could be ordered. I particularly want to try any of the white, black, red, Engelmann or Sitka spruce that are endemic to North America, although I know some might not be happy here.

Sitka spruce just happened to become available. A colleague brought these eight seedlings back from the coast up near the Oregon border, and will probably get a few more. They are prolific there, and get pulled like many other weeds. At the rate they are growing, they could get planted into a landscape even before we get any blue spruce! I am already very pleased with them.

For a while, I grew each of the six North American spruce, but only in cans. Since these Sitka spruce arrived, I have been wanting to get the other five. White spruce is ‘sort of’ here. Blue spruce will arrive soon enough.

Deciduous Evergreens

P91201Well, that is certainly a contradiction of terms. One might say it is an oxymoron. Decades ago, it really was how we classified what we now know more simply as ‘deciduous conifers’. There are not many of them. Ginkgo is a gymnosperm like conifers are, but is not really a conifer. Otherwise, there are only five other types of deciduous conifers, which defoliate through winter.

Laryx is a genus of about a dozen species that are known collectively as larch. Taxodium includes two species known as bald cypress, as well as a third evergreen species. Pseudolaryx amabilis, known as golden larch, Glyptostrobus pensilis, known as Chinese swamp cypress, and Metasequoia glyptostroboides, known as dawn redwood, are all three monospecific genera.

Some species of larch are common within their respective natural ranges. So are the bald cypresses. The others are quite rare. However, dawn redwood became a fad decades ago, so is not so rare in landscape situations. To those of us who expect all conifers to be evergreen, deciduous conifers seem to die suddenly in autumn. To some, it is not exactly a desirable characteristic.

The dawn redwood above lives in our landscapes. The tall evergreen trees behind it are native coastal redwood. Obscured by the yellowing birch to the right, a small giant redwood (another oxymoron) represents the third and only other species of redwood. The fall color of this dawn redwood appeals to some, but to others, it looks like one of the native redwoods abruptly died.

Our bald cypress below does not look so much like a dead redwood. The foliar texture and branch structure are quite distinct. The cinnamon brown fall color is actually rather appealing.

Of course, these pictures are nearly two weeks old. By now, both trees are likely bare because of the rain.P91201+

Evergreen Trees Drop Leaves Too

IMG_20141004_153228As the deciduous trees that will soon be coloring for autumn defoliate for winter, the evergreen trees will become more prominent. Some evergreen trees will drop some of their foliage along with deciduous trees through autumn and winter. Many drop some of their old foliage as new foliage develops in spring, or later in summer. All are on distinct schedules, but are never completely bare.

That certainly does not mean that evergreen trees are not messy. To the contrary, some happen to be significantly messier than some deciduous trees are. They are only evergreen because they do not drop their old foliage until it is replaced by new foliage. Whether individual leaves last just slightly longer than a single year, or for several years, they eventually shed and fall to the ground.

In fact, evergreen trees may shed small but pestering volumes of foliage for a few months or even constantly throughout the year. Some deciduous trees defoliate so efficiently within a very limited time once the weather gets cool, that all of their fallen leaves will be raked away within only two or three weeks. Of course, some trees, both deciduous and evergreen, drop flowers or fruit or both.

Not only do most evergreen trees shed for a longer time than most deciduous trees do, but most shed foliage that is not so easy to rake away. Cypress shed minute and finely textured leaves that are impossible to rake from lawns, but toxic if they accumulate. Juniper and arborvitae are easier to accommodate only because the trees are smaller. Fir, spruce and cedar have bigger needles.

Broadleaf evergreen trees are very different from coniferous trees. Their leaves are considerably easier to rake. They are generally more substantial than those of deciduous trees though. Some may not decompose so readily in deep groundcover. Southern magnolia leaves are notably slow to compost. Instead of producing cones, some broadleaf trees drop acorns or other messy seed.

Nonetheless, where there are compatible with their landscapes, evergreen trees are as practical as deciduous trees are.