Norfolk Island Pine

Norfolk Island pine seems to have been built rather than grown.

            In coastal areas of Southern California, the Norfolk Island pines, Araucaria heterophylla, are among the most distinctive large trees. Perhaps they are better described as ‘unusual’ . . . , or even ‘strange’. They are so symmetrical that they seem to have been assembled from prefabricated kits than to have grown as natural trees. Their strictly organized conical branch structures and remarkably straight central trunks are always visible through their uniformly open canopies. In such mild climates, they can get nearly a hundred feet tall and half as wide, so are not easy to hide. In Hawaii, their symmetry has actually made them popular as Christmas trees. Their finely textured juvenile foliage is comprised of narrow, half inch long pine-needle like leaves, which are wider among adult growth.

            Locally though, Norfolk Island pines are primarily enjoyed as houseplants, particularly since they can grow slowly and live in pots for many years. The climate is just a bit too cool in winter for them to be very happy in the garden. However, as they eventually get too large for their homes, many end up in the garden anyway. They stay much smaller and are not nearly as symmetrical as they are in milder climates, and may be damaged by the more severe frosts every few years, but they have a certain appeal and distinction regardless. Those that get planted in the garden while young seem to be more symmetrical than those that get disfigured by living as houseplants longer. For some reason, trees that develop weak or curved trunks as houseplants tend to continue to grow with interestingly irregular trunks and branch structure.

Atlas Mountain Palm

Atlas Mountain palm resists frost damage.

Mediterranean fan palm is a shrubby palm, with a few small trunks. Atlas Mountain palm, Chamaerops humilis var. argentea, is an even shrubbier variety. Mediterranean fan palm can grow slowly to about twenty feet tall. Atlas Mountain palm grows even slower to only about eight feet tall. Its several trunks become strikingly sculptural only after many years.

The primary allure of Atlas Mountain palm, though, is its distinctly silvery gray foliar color. Individual fan shaped leaves may be nearly two feet broad, with deep and narrow clefts. Petioles are so nastily thorny that grooming and pruning can be painfully difficult. Mature trunks can be six inches wide with dense coats of petiole bases. Bloom is not prominent.

Atlas Mountain palm is notably undemanding. Once established, it does not crave much water or fertilizer. Nor is it finicky in regard to soil quality. It is resilient to both extremes of heat and cold. After several years, it might benefit from thinning of superfluous trunks and pups. Like many palms, Atlas Mountain palm should perform well within big pots or tubs.

White Alder

White alder has a distinctive silhouette.

During the summer, the native white alder, Alnus rhombifolia, is a nice shade tree that looks bigger than it really is. By late winter, the bare deciduous canopy has an appealingly picturesque silhouette. This time of year is actually when white alder is typically less appealing, with dead foliage that provides no interesting fall color, but lingers until knocked down by rain or late frost. Yet, even now, it sometimes surprises with these funny looking floral structures that are interesting both in the early winter landscape, and with cut flowers.

In past decades, white alder was an ´expendable’ tree that was put into landscapes for quick gratification while slower but more desirable trees matured. By the time the desirable trees matured, the alders were removed to make more space for the desirables. This technique was practical because, like many fast growing trees, alders do not live very long, so start to deteriorate after about twenty five years anyway. However, alders often live longer than expected.

Mature alders are usually less than fifty feet tall where they are well exposed. They can get at least twice as tall where shaded by other trees or big buildings. Their plump trunks with mostly smooth silvery gray bark make them seem larger than they really are though. Too much water promotes buttressed roots which can displace pavement.

Firethorn

Firethorn berries are delightfully bright red.

Nothing is lost in translation. The botanical name of Pyracantha coccinea literally means “Firethorn red”. Firethorn is its common name. It produces bright red berries on wickedly thorny stems. Some old-fashioned cultivars produce bright orange berries. Cultivars that produce bright yellow berries are now rare. Fruit ripens for migrating birds about autumn.

The thorns of firethorn are difficult to work with. However, they make a hedge of firethorn impenetrable. Frequent shearing deprives hedges of their natural form and some of their fruit. Selective pruning is tedious and likely painful, but retains more berries. Pyracantha needs sunny exposure, but is otherwise quite undemanding. It is susceptible to fireblight.

The most popular cultivars of firethorn can grow taller than eight feet. Taller cultivars that can grow twice as tall are uncommon. Sprawling types initially stay quite low, but without adequate pruning, form thickets. These same sprawling types are conducive to espaliers on fences and walls. Because pyracantha is difficult to work with, it should not be left to get unruly.

Valley Oak

Foggy Oak Morning

‘Foggy Oak Morning’ by Karen Asherah, is another example of the local scenery that I miss while not taking a bus or walking. I drove past this scene for years on my way to work outside of San Martin without ever bothering to take a look at it. This happy tree is a native valley oak, Quercus lobata, like those that had been common throughout the Santa Clara Valley until only about two centuries ago. It is not exactly the sort of shade tree that everyone wants in a compact suburban garden, but is grand enough for large spaces like parks.

Mature specimens may not seem to get as tall as oaks in the Appalachian Mountains, but are actually the largest oaks in North America, and live more than five centuries. The tallest trees are mostly less than seventy feet tall, but can get taller. Trunks of the oldest trees are commonly six feet wide or wider. The distinctively and uniformly furrowed bark is as classically ‘oakish’ as the rounded prominent lobes of the deciduous leaves, and the sculpturally irregular branch structure. Odd stem galls, commonly known as ‘oak apples’, are home to the larvae of tiny wasps that rely on valley oaks for everything they need. Incidentally, Paso Robles, or ‘El Paso de los Robles’ is named for the valley oaks in the area, which Spanish immigrants thought resembled the ‘robles’, the European oaks that inhabit Spain.

More information about ‘Foggy Oak Morning’ can be found at the website of Karen Asherah at karenasherah.com.

European White Birch

European white birch exhibits elegant trunks.

European white birch, Betula pendula, is a team player. It usually inhabits landscapes in groups rather than singly. Some trees have two, three or more trunks. After all, its primary allure is its strikingly white trunks. Because its foliar canopies are not overly broad, a few can fit into limited space. It is an informal and relaxed tree with nicely pendulous growth.

Mature European white birches are not much more than fifty feet tall here. They can grow taller where winters are cooler. Their slender trunks are mostly less than a foot and a half wide. They generally lean with prevailing winds and away from shade. Their smooth and white bark develops rough and black furrows with age. Their little leaves are deciduous.

European white birch appreciates regular irrigation, so should perform well within lawns. It produces only moderate shade. ‘Laciniata’ has intricately lobed foliage and a narrower form. ‘Youngii’ is so pendulous that it needs staking to stand upright. It can not grow very tall. ‘Purpurea’ has bronzed foliage and somewhat tan trunks, but has become very rare. European white birch might self sow.

Mondo Grass

Mondo grass works as a small scale ground cover.

The thick clumps of evergreen grass-like foliage of mondo grass, Ophiopogon japonicas, make a nice lumpy ground cover for small spaces. Because it is rather tolerant of shade, and actually prefers partial shade to full sun, it works nicely under Japanese maples or highly branched overgrown rhododendrons. It gets only about half a foot deep. Narrow stems with small pale purplish blue flowers that bloom in summer are not too abundant, and are generally obscured below the foliage, but can actually get taller. ‘Silver Mist’ is variegated with white.

New plants are easily produced by division of large clumps. Overgrown or tired looking clumps can be shorn down at the end of winter, before new growth begins. Slugs and snails can be problematic.

Persimmon

Persimmons ripen as their leaves fall.

It lacks the spectacular spring bloom of the other deciduous fruit trees, but compensates. Persimmon, Diospyros kaki, performs double duty with fall color. Its autumn foliar color is impressively fiery orange. Then, it defoliates to reveal plump, abundant and comparably fiery orange fruit. So, it is spectacular with both autumn foliar color and autumn fruit color.

Persimmon trees are tempting. Some cultivars can grow twenty feet tall to become small or even mid sized shade trees. However, if they do so, much of their overly abundant fruit is unreachable. Aggressive and strategic pruning limits their production with most of their fruit in reach. Although undemanding otherwise, this major dormant pruning is important.

Persimmons are self fruitful without a pollinator. However, they supposedly provide more fruit of better quality with another cultivar. Fruit is unfortunately inedible before thoroughly ripe, but then all ripens simultaneously. That is an incentive to share with neighbors and friends. With a bit of effort, fruit is conducive to drying and freezing, although not canning. Ripe fruit is very perishable.

Candelabra Tree

Candelabra tree resembles cacti, but is not related.

The weirdly sculptural succulent stems of candelabra tree, Euphorbia ingens, dark green but devoid of any real foliage, are striking in the right situation. These stems resemble those of unrelated cactus, with longitudinal ridges topped with spines. Although botanically interesting, the minute greenish yellow flowers that bloom in autumn and winter on the ridges of the upper portions of the upper segments are not much to look at. Deep red seed capsules that turn purple as they ripen sometimes develop in milder climates after the flowers are gone, but are almost never seen locally.
Good exposure is preferred. Candelabra tree are better structured and more prominent standing alone away from other larger trees and shrubs. Cool winters and occasional frosts limit their height to not much more than fifteen feet; and unusually cold frost can actually kill big specimens back severely. However, in sheltered areas and milder climates, candelabra tree can get twice as tall. Soil should drain very well and get dry between watering. Regular watering can cause rot, particularly in dense or rich soil.
The main problem with candelabra tree is the remarkably caustic latex sap, which can be dangerous to children, chewing dogs or even those who need to prune the stems. Fortunately, candelabra tree needs very little attention, and only needs to be pruned where the stems get in the way or start to lean against fences or roofs. The caustic sap prevents insect problems.

Freeman Maple

Red maple combines with silver maple.

It combines the autumn foliar color of red maple with the lacier foliar form of silver maple. Freeman maple, Acer X freemanii, is a hybrid of the two. It occurs naturally where ranges of its parents overlap. However, most modern garden cultivars are products of intentional hybridization. Like silver maple, it does not need much chill to exhibit autumn foliar color.

Freeman maple inherits other attributes from both its parents. It combines rapid growth of silver maple with structural integrity of red maple. Although it gets bigger than red maple, it is not as imposing as silver maple. It develops high branches like silver maple, but also is symmetrical like red maple. Big roots are about as complaisant as those of red maple.

Mature Freeman maple trees can grow about forty feet tall and broad. Autumn foliar color is vivid orange and red, and lasts longer than that of red maple. Since Freeman maple is a hybrid, it is mostly sterile. It can not generate an annoying abundance of seed. Nor can it naturalize in favorable climates. It is an exemplary maple for mild climates such as this.