Eucalyptus citriodora, lemon gum, is one of several species that I miss from the more southern portion of the Central Coast and Southern California. San Luis Obispo, where Brent and I studied horticulture at Cal Poly, and where I learned to appreciate this particular species, is technically within the same climate zone as Los Gatos. Nonetheless, many species that are popular in Southern California are more popular there than here, perhaps because of the proximity to Southern California. I got this picture on the inland edge of Highway 101 in Carpinteria on the return trip from Los Angeles. It demonstrates how sculptural the elegantly slender, smooth and pallid trunks and limbs of lemon gum are. The airy foliage is delightfully aromatic, but is too high to reach among trees that are sufficiently mature to be so sculptural. A few other eucalypti are similarly but distinctly sculptural. Some develop heftier trunks and limbs. Some develop blotched or uniformly coarse bark. Also, several other genera, such as coast live oak, camphor and ‘Marina’ madrone, develop sculptural form. Such form should be more of a consideration for modern landscape design, as it was until about the late 1970s, when trees like European white birch and the last of the complaisant eucalypti slowly became passe. It is actually gratifying to notice that a few daring horticulturists are experimenting with some of the smaller species of eucalypti that could have become popular years ago, as well as a few that had not yet been introduced. Where lemon gum might eventually grow too large, smaller species, such as Eucalyptus caesia, gungurru, might be more proportionate. Of the more than seven hundred species of Eucalyptus available, more than a few must be appropriate to refined home gardens, and more than a few of such are likely sculptural.
Giant redwood, Sequoiadendron giganteum, is famously the largest tree in the World. Although not quite as tall as the coastal redwood, Sequoiadendron sempervirens, it is bulkier. It grows taller than three hundred feet, with trunks wider than thirty feet, to weigh more than six hundred thirty tons.
Yet, like many species, it has at least one cultivar. ‘Pendulum’, which is the weeping giant redwood, is nothing like the simple species. It might grow forty feet tall, if it is able to support itself at such a height. It’s canopy might grow a few feet wide, but it really cascades more than it reaches outward. It really is weird. It looks more like a relative of Mr. Snuffleupagus of Sesame Street than like a relative of giant redwood.
Of course, its weirdness is what makes it so appealing. It is sculptural. It is bold. It really makes one wonder what planet it is from.
I got this picture in Kitsap County in Washington, hundreds of miles from the native range of the simple species within the Sierra Nevada. Actually, I see more of this cultivar in the Pacific Northwest than here. It likely performs better there because of the colder winter weather. Furthermore, this weird cultivar is more popular than the simple species, partly because it is so distinctive, and partly because it is more proportionate to home gardens. Simple giant redwoods only fit into very spacious landscapes.
Weeping giant redwood may not be good for anything more than its weirdness, but at least it excels at that. Otherwise, it provides no significant shade. It does not bloom conspicuously. It provides no fruit. It does not even make good firewood. Fortunately, weirdness has certain appeal. Within our home gardens, we can grow what we like, even if merely for its weirdness.
These coastal redwoods are very distinct from giant redwoods.
“Hidden giants: how the UK’s 500,000 redwoods put California in the shade” was published in the Guardian more than a month ago. It was amended to specify that it is about giant redwoods rather than all redwoods, as if that is a distinction that is easily omitted. Incidentally, it later mentions that, “For millions of years, the world’s tallest trees have graced California peaks and coastlines,” which is a reference to coastal redwoods, which are a different genus from giant redwoods.
What is worse is the claim that, “Researchers found that the Victorians brought so many seeds and saplings to Britain that experts say the giant redwoods now outnumber those in their US homeland.” More specifically, it continues to explain that, “The Victorians were so impressed that they brought seeds and seedlings from the US in such large numbers that there are now approximately 500,000 in Britain, according to a Forestry Commission estimate that includes coastal redwoods and dawn redwoods (a separate Chinese species) as well as the giant redwoods. Experts at Kew think most of the UK trees are giant sequoias, the official name for giant redwoods. California has about 80,000 giant redwoods, as well as also having coastal redwoods and a few ornamental dawn redwoods imported from China.”
Essentially, the article claims that this data demonstrates that there are more redwoods in the United Kingdom than there are here. Apparently, approximately half a million redwoods live there, and “experts” “think” that most are giant redwoods. Also apparently, only about eighty thousand giant redwoods live here.
Response to this is no easy task. It is a comparison of all redwoods in the United Kingdom to a very slim minority of redwoods here. About eighty thousand mature specimens of giant redwood live in the wild alone. Countless more immature specimens, including abundant seedlings that are only a few years old, live with them. Countless more giant redwoods have been installed into landscapes throughout areas of California that are collectively almost as large as all of Britain. Such trees have been getting planted here at least as long as they have been getting planted there. It is impossible to estimate how many giant redwoods are here, but there are many more than merely half a million. Furthermore, regardless of how the article was revised, the half a million redwoods of the United Kingdom includes coastal redwoods and dawn redwoods. There may be as many dawn redwoods here as there are there. More importantly, there are more than two million acres of wild coastal redwood forest here. In other words, for every redwood of any species there, there are at least four acres of wild coastal redwoods here. Many redwoods inhabit each acre of redwood forest. Also, many millions of coastal redwoods are planted into landscapes here.
Incidentally, the three species of redwood are actually three distinct genera, and the official name of giant redwood really is giant redwood. It is Sequoidendron, not Sequoia.
The article continues to say with complicated grammar, “Spurred by the climate crisis, devastating droughts and scorching temperatures have added new stressors for the redwood, particularly the famous giant sequoias, which now struggle to bounce back after big wildfires.” However, there is no climate crisis with devastating droughts or scorching temperatures here. Summers here are naturally dry and warm. That is simply how the climate here is. Most forests here burn at least every century or so. Therefore, redwoods that are thousands of years old have survived many fires. Now that some forests are allowed to burn as they naturally should, fires will not likely be so unusually lethal to younger redwoods in the future. Another claim that, “Vulnerable trees are also increasingly under attack from native bark beetles, insects that feed on their spongy red trunks until they topple.” is likewise inaccurate. Bark beetles rarely damage redwoods, and are no more likely to damage them now that they ever had been.
The landscape in front of the home across the road from where I am staying in Arizona is weird. Like many of the landscapes here, it is simple, with only a few small shrubs and stone surrounded by gravel, but also includes this silly pair of purple leaf plum trees. They are pruned into symmetrically round form. The pruning keeps their canopies nicely dense with strikingly bronzed foliage. What makes them so weird is their location. Within the climate here, shade is an asset. However, these trees are not allowed to make much shade. The natural form of these small trees could frame the facade of this house nicely. However, they clash with it defiantly. With their profuse spring bloom and rich foliar color, these trees might enhance the scenery from within the windows. However, they subjugate it and exclude any other scenery, and likely exclude a bit too much sunlight without providing significant cooling shade through summer. I am certainly no landscape designer, but in my opinion, this landscape looks odd. The vegetation is of good quality and quite healthy. The stone and gravel is neatly arranged. The facade of the home is quite appealing. The problem is that the assemblage of the landscape relative to the home is awkward. The tree in the foreground is one of the first three mesquite trees that I ever met when I pruned them up for clearance last year. It and the specimen next to it are also awkwardly placed in front of their home, although the third is in a better situation next to the garage. That is precisely why these three trees were pruned up for clearance, and why they will be pruned higher as they grow. They already provide a bit of shade, and will provide more as they grow.
Flowering crabapple is more colorful than crabapples that are grown more for fruit.
This picture resembles flowering cherry, but is actually a flowering crabapple, Malus spp.. Both provide impressively abundant spring bloom before foliation in spring. Both may have single, semidouble or double flowers in various shades ranging from white to rich pink. Some flowering crabapples though have nearly red flowers. Flowering crabapples get slightly larger, more than twenty feet tall and broad; but some stay as short as five feet, and others get taller than thirty feet! Some have bronzy or purplish foliage through summer. The half inch to nearly two inch wide yellow, orange or red fruit can be colorful into autumn, and some makes good jelly; but it can also be messy. The main advantage of flowering crabapples is that they are somewhat less susceptible to rot than flowering cherries are in dense slowly draining soil.
Flowering cherry is the fruitless counterpart of fruiting cherry.
Like camellias and chrysanthemums, the many different varieties of flowering cherries, Prunus spp., have been developed by horticulturists in Japan for centuries. There are now almost too many to choose from. Most stay less than about twenty feet tall and broad, so are proportionate to compact gardens. A few stay even smaller. The classic Yoshino flowering cherry can get somewhat larger. Weeping cherries have pendulous branches. Columnar types are noticeably taller than wide, at least while young. Some flowering cherries have remarkable fall color.
Despite my preference for cherry trees that produce cherries, I can not deny that the spring bloom of the innately non-fruiting flowering cherries is spectacular! Most bloom before any foliage develops. Their flowers can be single, semidouble or double, in various shades of white or pink, including rich rosy pink. They can not be very messy without fruit. Unfortunately though, flowering cherry trees are susceptible to rot in the endemically dense soil, so should not be watered too much.
Oakland, fifty miles north of here, was named for the oaks that formerly inhabited it. Imagine that! Although valley oak, Quercus lobata, is native, and assumed to be the origin of the regional name, coast live oak, Quercus agrifolia, was likely more abundant there at the time.
Of the many other towns in California with horticultural names, a few are also named for unspecified oaks, including del Rey Oaks, Oakdale, Oakley and Thousand Oaks. Encinitas, Live Oak and the Encino neighborhood of Los Angeles are named more specifically for coast live oak. Paso Robles is named more specifically for valley oak.
Oakland and Oakridge are the only two towns that I could find in Oregon that are named for Oaks. I suspect that Oakland is named for Oregon white oak, Quercus garryana, only because that is the most prominent species of oak there. It is also native here, although I am not aware if I have ever encountered it locally. It resembles small specimens of valley oak, which, incidentally, is also known as California white oak.
This picture of a few main limbs of an exemplary specimen of Oregon white oak is from Cabin Creek Rest Stop on Southbound Highway 5, just north of Oakland in Oregon. To me, it looks sort of Californian, like something that, a long time ago, was more prominent in Oakland here in California, on ‘the Bright Side of the Bay’.
In the right situation, Victorian box, Pittosporum undulatum, is a nice small to mid-sized shade tree with dense foliage, sculptural branch structure and pleasantly fragrant spring bloom. In the wrong situation, it drops enough leaves, flowers and sticky seeds and bits of seed capsules to make quite a mess. This finely textured and sometimes sticky debris is easily absorbed into thick, shade tolerant ground cover like Algerian ivy, but is difficult to rake from pavement and to clean from roof gutters. Besides, even though Victorian box is not a large tree, the roots can eventually become aggressive enough to displace pavement.
Young trees grow rather vigorously to about ten feet tall and wide, and then slow down somewhat as they continue to grow to as much as three times as tall and wide. They are easily contained with occasional selective pruning. The small, clustered flowers are not as impressive as their fragrance, adding only a bit of pale yellowish white color over the exterior of the rounded canopy. Some people, as well as birds, like the greenish olive-sized fruit that turns orange and eventually splits open to reveal sticky orange seeds within. (‘Pittosporum’ translates into ‘sticky seed’.) Leaves are about two or three inches long, or longer, with ‘undulating’ margins.
Many trees get too big for many situations. Trees should be proportionate to their spaces.
Japanese maples are among my least favorite of trees. There; I said it! Even though I can not think of any single species of tree that has so many distinct and fascinating cultivars, I am bothered by how Japanese maples have been denigrated by their own overuse. That which is naturally an understory tree (lives in the partial shade of larger trees), which should be thoughtfully selected for its individual form, texture and color, to function as a focal point specimen tree, has become too common and misused.
Every tree should be thoughtfully selected for its particular application. The ultimate size, shape, shade, potential mess, cultural requirements, root characteristics and foliar characteristics (evergreen or deciduous) all need to be considered. Japanese maples are certainly appropriate for certain applications, but not every application. The same goes for London plane, crape myrtle, Chinese pistache and any overused tree.
Crape myrtles and Japanese maples are popular partly because they do not get too big, and are proportionate to small spaces. However, they do not get big enough for other situations. Although a silver maple will not fit into an atrium as well as a Japanese maple would, it is a much better shade tree for a big lawn. Italian cypress can actually get taller, but its very narrow shape makes a minimal shadow. Monterey cypress gets broader, but the shade is too dark for lawn.
Unfortunately, there is no such thing as a perfect tree. Jacaranda is of moderate size, has a good shape, and makes medium shade, but is quite messy, particularly over pavement. Silk tree is both messy and has aggressive roots that can break pavement, but just like jacaranda, it looks great and is not a problem surrounded by ground cover. Both are deciduous, so allow warming sunshine through in winter. An evergreen tree that would be better to obscure an unwanted view should not get so large that it also blocks a desirable view for a neighbor.
Palm trees are very different from all other trees in that they have no branches, only leaves. As they grow out of reach, they will need to be groomed by professional arborists. Palms only grow upward, and can not be pruned around utility cables. They will need to be removed if their trunks get too close to high voltage cables.
I certainly do not intend to convince anyone to not plant any trees. I merely want people to consider the variables involved with the selection of trees that are appropriate to each particular application. Trees are long term commitments. Problems caused by improper selection can be difficult or impossible to correct later.
Silver wattle is an aggressively invasive exotic species, but certainly is pretty in bloom!
From my window, I can see across the way to one of my all time favorite weeds in my neighbor’s garden. A healthy acacia tree is nearly in full bloom! Throughout the year, I occasionally remind my neighbor that we really should cut the tree down before its seedlings overwhelm the neighborhood. This time of year though, I am secretly glad that we have not gotten around to it yet.
Even though most people find the fragrance objectionable, I actually find it appealing. It reminds me of Southern California, perhaps because, even on a cool wintry day, it smells like a sun roasted freeway on a hot smoggy day. I suppose that its pollen is a problem for anyone with even mild allergies; and after all, it is still a major weed.
Other trees that are now blooming are not so problematic, or equipped with a petroleum based fragrance. Shrubby forsythia and flowering quince were the first to bloom. Forsythia is the best bright yellow besides acacia. The most popular flowering quince are rich pinkish orange. Apricot, cherry, peach, plum, prune, nectarine, almond and a few other fruit trees, as well as their fruitless ‘flowering’ counterparts, including purple leaf plum, are blooming about now. (Flowering apricot, peach, nectarine and almond are rare.) Fruiting pear and apple trees typically bloom a bit later; but flowering pear and some flowering crabapple are already blooming. Later, redbuds bloom bright purplish pink.
When pruning fruit trees during winter, I sometimes leave a few branches to cut and bring inside while in bloom. Fruitless flowering trees do not need to be pruned like fruiting trees, so can provide even more flowering stems with more flower variation. Stems of forsythia, flowering quince and flowering cherry are often ‘forced’ into bloom by getting cut and brought in just as flower color start to become visible, so that they can finish their bloom inside. Except for redbud, any of the other spring bloomers can also be forced, but are more likely to get desiccated by the dry air inside.
As red maple and red oak begin to break dormancy, they develop delicate pendulous ‘blooms’ that are not very colorful, but might be interesting enough to add to more colorful cut flowers. Of course, pussy willows are always traditional.
Tony Tomeo 