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Horridculture – Redwood Fallacies

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.

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More Bad Design

blindfolded house

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.

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Flowering Crabapple

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.

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Flowering Cherry

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.

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Oakland

Oregon white oak, Quercus garryana

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’.

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Victorian Box

Victorian box does not get too big.

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.  

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Selection of Appropriate Trees

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.

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Spring Blooming Trees

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.

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More Palm Silliness

Mexican fan palm, Washingtonia robusta

Mexican fan palm, Washingtonia robusta, is the most familiar palm throughout most of California. It is most typically groomed to remove deteriorated leaves without removing the associated toughly fibrous petiole bases that form a neat lattice-like sweater of stubble around its trunks. Some are groomed to also remove the stubble, leaving a clean shaven and leaner looking trunk. Some are shaven only part way up, with a sweater higher up. Without grooming, or if grooming discontinues, some accumulate beards of deteriorated leaves. Although generally harmless, such beards are combustible and can be infested with rats. On rare occasion, they become dislodged from their trunks and fall. They are dangerously heavy and very messy. This silly looking Mexican fan palm was groomed part way up, and then neglected long enough to accumulate a significant beard. The beard then fell, leaving the bare trunk exposed. Only the few lowest of the old leaves remain below where the beard was. A new beard is now forming above.

Queen palm, Arecastrum romanzoffianum, was an uncommon palm until it suddenly became very popular and almost too common through the 1990s. By that time, selective breeding produced the standardized modern variety, which is a bit greener, fluffier and more vigorous than most old specimens. Although it is a bit more genetically conformative than old specimens, it still exhibits genetic variability. Unless some are cloned by tissue culture, all are grown from seed. Some grow slower, so stay shorter. Some develop unusually plump trunks. Some are unusually floppy. This one is just weird. Its foliar canopy is so strictly narrow that it resembles the locally rare Andean wax palm, Ceroxylon quindiuense. Perhaps it actually is an Andean wax palm! A pindo palm, Butia capitata, lives in the associated front garden, and it is not exactly common.

queen palm, Arecastrum romanzoffianum or Andean wax palm, Ceroxylon quindiuense or something else?
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Palm Ignorance

Bismarckia nobilis

Many years ago and before I started writing my gardening column in response to all the horticultural misinformation that I had been observing in the San Jose Mercury News, I heard some of the most idiotic commentary I have ever heard about palms on the radio. I do not remember what radio station it was broadcast from, but it was likely in San Jose. The commentator was expressing his disapproval of the many mature palms that were being incorporated into public landscapes there at the time. He started by stating that, “There are two kinds of palms . . . ” Well, that certainly got my attention. He continued to say, ” . . . the tall skinny kind and the short fat kind.” Wow, I can not forget a comment like that. I knew that he was referring to Mexican fan palm and Canary Island date palm, which were and probably still are the most common palms in San Jose. Also, they were the two species that were so commonly installed into public landscapes at the time. There was no mention of queen palm, windmill palm, Mediterranean fan palm or California fan palm, all of which also inhabit San Jose. Since then, queen palm and the formerly rare pygmy date palm have become more common than they had been. Hesper palm remains rare. I brought three distinct species of bamboo palm from Los Angeles, and would like to bring a few more of the palms that perform well there, even if they do not perform so well here. I happen to be fond of the few types of king palm. I very much want to procure Bismarck palm like this one. Although still uncommon in Los Angeles, it is not completely rare. No one knows how well it performs here because no one has tried it yet.