Coast Live Oak

90522The valley oak of the Sacramento Valley, San Joaquin Valley, and coastal valleys to the west, is the grandest oak of North America. Within the coastal half of that range, and extending down past San Diego, the coat live oak, Quercus agrifolia, is a nearly comparable second grandest. The biggest subjects may be as tall as seventy feet, and nearly as wide, with trunks wider than ten feet!

However, there is significant variability. Trees in forest situations do not get as big, and may stay lower than twenty five feet, with shrubby branch structure. While the biggest can get older than two centuries, smaller trees may not live half as long. The canopies of exposed solitary trees might reach the ground, while more social or sheltered trees are likely to shed lower growth with maturity.

Coast live oaks are typically pretty gnarly, and many have multiple flaring trunks. The dark evergreen leaves are only about an inch or two long, and half as wide, with bristly teeth on convex edges. The narrow inch long acorns can be messy. Roots are very sensitive to excavation and excessive irrigation. Sudden Oak Death Syndrome prevents new trees for getting planted in many regions.


The Other Rhodies

P90504KThere are countless species and cultivars of rhododendrons. Some have been in cultivation for centuries. Their big bold blooms are spectacular against a backdrop of their dark evergreen foliage. They prefer shelters spots, and some are happy to bloom in places that are too cool and too shaded for other flowers to bloom so well. They are so impressive that no one notices that they lack fragrance.

There is certainly a lot of variety among rhododendrons. Some are low mounding shrubs, while other can grow as small trees with open branch structure. Flowers can be white, pink, red, purple, blue or maybe even yellow or orange. Most flowers have some sort of pattern within the main color, but some are solid colors. Nonetheless, regardless of all the variety, we think that we can recognize a rhododendron when we see one.

Then there is Rhododendron occidentale, the Western azalea. The flowers are sort of recognizable as either big azalea flowers or lean rhododendron flowers, but are quite distinct from what we think of as familiar rhododendron flowers. The color range is very different too, with more white, marked with yellow, pink or orange. Even more surprising is that the bloom is quite sweetly fragrant!

Foliage is also very different from what is expected from a rhododendron. Not only is it deciduous, but if well exposed, it can actually develop soft yellow, orange or brownish red color in autumn. Individual leaves are rather narrow and papery.

We have only a few Rhododendron occidentale at work. They are not as tolerant of the partial shade from the redwoods as the more familiar rhododendrons are. However, they do happen to be blooming exceptionally well this year, while the bloom of the more familiar rhododendrons is less impressive than it has been in many years.

Santa Cruz Island Ironwood

60504A few years ago, it was known as Santa Catalina Island ironwood. However, the rare subspecies native to Santa Catalina Island lacks the distinctively angular foliar lobes of the Santa Cruz Island ironwood, Lyonothamnus floribundus ‘aspleniifolius’. The evergreen compound leaves are about five inches long and four inches wide with three or five narrow leaflets, and look like chicken feet.

Young trees can grow at an impressive rate, but rarely get to thirty feet tall, which is only half as tall as they get in the wild. Most stay rather narrow, and shorter than a two story house. They work nicely in groves, but not as symmetrical groupings. Each tree has a unique personality and form, and some stay smaller than others. The finely shredding bark fades from cinnamon brown to gray.

Six inch wide trusses of tiny white flowers bloom late in spring or early in summer. These circular trusses are flattened, similar to those of toyon but larger. They fade to brown and can hang among the foliage for years. Older trees bloom more than vigorous young trees do. Deteriorating older trees can be cut to the ground and allowed to regenerate with fresh new growth from their stumps.

The Overlooked Trillium

P90407Other species must be more interesting than what is native here. There are supposedly as many species of Trillium as there are of Yucca; forty-nine. All but ten are native to North America. The others are in eastern Asia. They are desirable and respected perennials to those who are familiar with them. White trillium is the official wildflower of Ohio, as well as the official floral emblem of Ontario. Ours would not likely qualify for such status.

The few around here appear only briefly about this time of year, and bloom with these small purplish burgundy flowers. They are only a few inches high, so are easy to miss. By the time they get noticed they are finished with their bloom. Their foliage lasts only until the weather starts to get warm in late spring or early summer. During their brief season, they somehow manage to store enough resources to repeat the process for many years.

This particular species is supposedly known as ‘giant wakerobin’, or Trillium chloropetalum. It is so diminutive, that I can not help but wonder about those that are not ‘giant’. Others that I see around here have more rusty red or ruddy brown flowers that stay closed most of the time. Western trillium, Trillium ovatum, lives here too; and I may have seen its foliage without distinguishing it from giant wakerobin, but I have never seen it bloom.

The trilliums that are native here live in partial shade out in forests, but away from more aggressive plants. They do not transplant easily, and do not like refined gardens.

Other trilliums in other regions bloom with bigger flowers in white, pink, red, purple, pale yellow or green. They must be more impressive than ours, and should at least be more adaptable to home gardens and landscapes.


90123Botanists took a while to contrive an identity for toyon, which is also known as Christmas berry and California holly. It was classified as a species of Crataegus, two different specie of Photinia and two other specie of Heteromeles before it was finally identified as Heteromeles arbutifolia. Meanwhile, the town named after it changed its name only once from Hollywoodland to Hollywood.

Toyon is native to the coastal chaparral regions of California and Baja California, as well as British Columbia, so it can be quite happy with minimal watering or none at all in home gardens. Too much water is likely to rot roots. Fire blight unfortunately seems to be more of a problem in refined landscapes than it is in the wild. Toyon can be pruned up as a small tree, but must not be shorn.

Where it competes with other trees, toyon can get more than twenty feet tall. Those that are well exposed are typically less than twelve feet tall, with nicely well rounded canopies. The evergreen leaves are somewhat serrate and narrow. Fluffy trusses of small white flowers bloom early in summer. Big hanging clusters of bright berries ripen in autumn and linger until birds eat them in winter.

Rhus diversiloba / Toxicodendron diversilobum

P81209This would be a good topic for one of my rants on Wednesday, except that it is too silly for that.

Many years ago, before I started writing my gardening column for our local newspapers, my colleague Brent and I used to exchange funny newspaper gardening articles. Some were obviously not written for local climates. Some were just very inaccurate. Back then, it was done by mail, so the articles were added to anything that we happened to be sending to each other at the time. If I sent him some seeds, I would add an article or a few from the San Jose Mercury News. If he sent my cuttings, he would add an article or a few from the Los Angeles Times. They eventually became the inspiration for my gardening column, when Brent and others told me that rather than making fun of the inaccuracies of the articles, I should provide accurate articles.

One of the silliest that Brent sent to me was an otherwise well written article about star jasmine. Most of the information about it was accurate, until it got to describing the colors of the exclusively white bloom. The article explained that star jasmine bloomed in vivid shades or blue, purple, red, orange and yellow; just about every color except for white!

Well, I topped that with an article about protecting Japanese maples from theft, which sounded crazy even before reading the article. There were three recommendations. The first was to surround the subject Japanese maple with razor wire. Ah, the ambiance! The second recommendation was to dig a hole about as big as a trash can and fill it with concrete with a curved piece of rebar to make an enclosed loop on top, and then chain the subject Japanese maple to it. How about we just do without a Japanese maple in the front yard in a neighborhood where we expect it to get stolen. The third recommendation was to plant poison oak around the subject Japanese maple. Yes, good old fashioned poison oak, Rhus diversiloba, which is also known by the more descriptive Latin name of Toxicodendron diversilobum, and commonly available at . . . . some nursery . . . . somewhere. . . . You know, one of those . . . . garden centers . . . . or something.

Silly? Yes! What is sillier is that poison oak really IS available from certain nurseries that sell native specie! What is even SILLIER than that incredible degree of SILLINESS is that one of the so-called landscape companies that I worked for in about 2006 actually procured some for habitat restoration outside of, but adjacent to a newly landscaped area on the banks of where the Guadalupe River flows through San Jose. Poison oak and other native vegetation needed to be eradicated for the installation of the new poison oak and associated irrigation system, because nothing is more natural than supplemental irrigation! Then, the ‘gardeners’ had to conduct regularly scheduled weed abatement so that poison oak growing from seed tossed by the pre-existing poison oak did not grow up and compete with the new poison oak in the new ‘natural’ ‘landscape’. We certainly would not want poison oak taking over the poison oak.

Okay, this is not Wednesday, so I will finish this rant.

Poison oak happens to provide some of the best orange and red autumn foliar color in our region where almost all of such color is simple yellow. Where it is out of the way and not bothering anyone, it is sometimes left to climb high into trees, where it colors almost as well as flowering pear. Yes, it is pretty, but I will not be planting any of it.P81209+

My First Tree

71108Calocedrus decurrens. Incense cedar. The first tree that I ever planted was a small incense cedar, like the tree in the picture here. Of course, it was not this big when I planted it.

It came from my maternal grandparents’ cabin near Pioneer, in the foothills of the Sierra Nevada. It was a wild seedling that might have been pulled up because it was where the cabin was to be built. My grandmother planted it into a small wooden planter in the backyard. Once it recovered and started to grow, she gave it to my parents, who had me plant it on a small hill in the back yard. Although not native to the Santa Clara Valley, it did well, and grew tall and lean. I tend to compare all incense cedars to my first tree.

Almost all are older and bigger, with plump trunks. I can guess from their age that most were planted during the Victorian Period. Quite a few were planted half a century later, during the 1950s, when Monterey pine and Monterey cypress were too commonly planted. Not many incense cedars are young. It is as if they had been available in nurseries until the early 1970s, and were not grown much after that. I planted a few in Scott’s Valley back in the 1990s, on the southern margin of what is now Sky Park, but only because my colleague happened to grow them.

Because it was less expensive to transport ‘relatively’ local lumber than to import Eastern red cedar lumber from the East, incense cedar provided the veneer for closets of old homes here, as well as cedar chests. Small groves of incense cedar were grown in the Santa Cruz Mountains as a local source of cedar wood. Now that cedar closets and chests are no loner necessary to repel moths from woolens and furs, the naturalized groves are abandoned, and now grow wild. I know that they are technically not locally native, but I still like to see a few of them around. They look so much like my first tree.

California Black Oak

81003The most popular hardwood in California is essentially unavailable in nurseries. California black oak, Quercus kelloggii, provides between a quarter and a third of the hardwood timber harvested in California. One would not know it by its sporadic appearance within mixed forests of the Coastal Ranges. It is much more common in the Sierra Nevada, which might be why no one grows it.

Mature trees can top out at thirty feet with broad canopies if well exposed, or might be more than seventy feet tall and relatively slender if they must compete with other trees. The biggest trees are more than a hundred feet tall. The sculptural trunks are usually less then four feet wide. Trunks of old trees are commonly rotten inside. Gray and smooth young bark gets rough and dark with age.

The distinctively lobed deciduous leaves of California black oak are not much more than four inches long. They can get nearly twice as long on the most vigorous growth, or where shaded. The dark green foliage will slowly turn brown or yellow through autumn, and then defoliate through winter. It can turn a brighter yellow or orange, but then defoliates faster, if the weather gets cool fast.

Corndog Orchard

P80728KUrban sprawl replaced the formerly vast orchards of the Santa Clara Valley a long time ago. Nowadays, it is difficult to imagine that they were ever here. Apricots, prunes, cherries, almonds, walnuts and all that the region was once famous for are all now rare commodities.
Only a few minor corndog orchards remain. They survive only because they are not actual orchards that are grown on land that is useful for something else, but instead grow wild on otherwise useless marshland and along the few creeks that flow through the region. Some marshland that could not be converted into usable space was developed into parks, and within many such parks, the remaining marshlands are protected as native habitat.
Vasona Lake County Park and the small Vasona Lake within were once a large marshy area that sustained what was probably the biggest corndog orchard within the Santa Clara Valley. It is at the transition where the Los Gatos Creek flows swiftly from the slopes of the Santa Cruz Mountains, and then slows as it reaches its flat alluvial plain within the Santa Clara Valley. Although not nearly as abundant as they were prior to development, corndogs still inhabit the banks of Los Gatos Creek and Vasona Lake. We know them as cattails.
Because they are a native species that had historically been more common locally than anywhere else nearby, and because of their common name that is coincidentally associated with cats, cattails had been nominated to be the official Town Flower of Los Gatos (which is Spanish for The Cats). There are not many natives that would be as appropriate, and the only comparably culturally significant flowers would be those of the old fruit orchards, such as apricot blossoms. No other flower is both native and so culturally significant.

Nature Is Messy

4This sort of weather pattern does not happen very often. Late spring is normally pleasantly warm, and the weather gets progressively warmer through summer, which typically includes a few unpleasantly warm days. It rarely gets too hot here, and when it does, it does not last for more than a few days, and tends to cool off at least somewhat at night. The air is normally arid. Humidity is uncommon in a chaparral climate.
While so many in the Northern Hemisphere were experiencing unseasonable warmth, the weather here was unusually mild. When the weather became warm, it did so suddenly. There was nothing unusual about the warmth. It was well withing the normal range for this time of year. The suddenness of the change was what made it unusual.
Humidity complicated matters. Again there is nothing too strange about humidity. Although rare, it does sometimes happen. The problem was that it happened at the same time that the weather suddenly changed from pleasantly mild to somewhat warm.
This combination of the weather changing so suddenly from mild and arid to warm and humid caused an outbreak of spontaneous limb failure. It was very evident in Felton Covered Bridge Park, where several trees that experienced it could be observed in the same place.5
The most recent victim was the biggest old California sycamore in the area. Half of the top of the canopy broke away and got hung up on an adjacent trunk, but started a cascade of other limbs that broke off more major limbs all the way to the ground. A large cavity that contained a very established beehive was exposed. A car parked below was clobbered (but somehow sustained only minimal damage!). The remaining trunks and limbs of the old sycamore are now even more scarred and disfigured than they were before this happened. The biggest gash is about fifteen feet long! What a mess!
Spontaneous limb failure is technically very damaging to the trees who experience it, but not all of them see it that way. Many of the riparian trees that are so inordinately susceptible to it might use it to their advantage. Fractured limbs that remain attached to the original tree while they sag onto the ground can develop roots where they touch the soil, and develop into new trees. These new trees are more stable at first, but eventually develop structural inadequacies like their parents did, and repeat the process. Willows excel at this technique. Cottonwoods and box elders do it too. Sycamore do it only rarely, but sometimes destabilize and fall over so that some of their limbs can grow into new trees as the original trunks decay. It may not be the sort of behavior that we want in our home gardens or parks, but as far as the trees are concerned, it works.6