One of the big four for mild climates, sweetgum, Liquidambar styraciflua, develops an excellent display of mixed yellow, orange and red, regardless of how quietly autumn tries to sneak in. Of the other three, Chinese pistache is more orange with less yellow, flowering pear is more ruddy, and gingko is only bright yellow. They all get very flashy color, but sweetgum just might be the flashiest.
Some trees can favor one color or another. Distressed trees tend to be more pinkish red. Vigorous trees might have more yellow. Garden varieties were selected for reliable variability; although ‘burgundy’ has more dark red. Only trees that are too sheltered, too vigorous or pruned too aggressively will lack color. Urban trees can get fifty feet tall, but do not get very broad. Structural deficiency, aggressive roots and spiky seed capsules the size of ping pong balls can be problematic.
From a simple picture, Spanish bayonet, Yucca aloifolia, is indistinguishable from the common giant yucca. The narrow leaves are about two feet long, and flare upward and outward from terminal buds. Plump conical trusses of waxy white flowers with purplish highlights stand vertically just above the foliage. The main difference is that the leaves are more rigid than they appear to be, with nastily sharp terminal spines.
Like redwoods, the cork oak, Quercus suber, is a ‘pyrophyte’, which means that it survives forest fires that burn off competing vegetation. The trunks and main limbs are insulated with a very thick bark. Only the foliage and smaller stems burn off. After a fire, the upper limbs of cork oak regenerate new foliage while other less fortunate plants start over from their roots or seed at ground level.
Bluegum is famously problematic. It is too big, too invasive, too messy, too structurally deficient, and as demonstrated in the Oakland fire, too combustible. Dwarf bluegum, Eucalyptus globulus ‘Compacta’, is a completely different animal that does not even look related. It gets only about fifty feet tall, with a dense and somewhat symmetrically rounded canopy. The mess and falling limbs do not affect such a large area.
In the west, the incense cedar, Calocedrus decurrens, was made into cedar chests or paneling for cedar closets as a substitute for the more traditional Eastern redcedar (which is incidentally a big juniper). The wood is supposedly aromatic enough to repel moths from woolens and furs. The evergreen foliage is very aromatic as well, so is sometimes used for garlands at Christmas time.
It is really an evergreen shrub with limber stems; but lavender starflower, Grewia caffra, can work almost like a rambling vine. It does not actually climb or grip anything. Like the canes of a climbing rose, it can be tied onto a trellis or fence as an espalier. As a free standing shrub, the arching stems should be pruned selectively. Shearing deprives them of their natural form, and inhibits bloom.
Yuccas are almost as useful as aloes are for gardening in chaparral or desert climates. I say ‘almost’ because most are not quite as friendly. The leaves are outfitted with nastily sharp tips. It is how they protect themselves from grazing animals in the wild, but it is not such an advantage in home gardens. Some actually have the potential to be dangerous where someone could bump into them. The leaves of Joshua tree can puncture leather. Some types of yucca get so big that they make it difficult to avoid their nasty leaves, even if planted in the background.
We really should be growing more of what grows well here. This is as relevant in other regions as it is in the Santa Clara Valley. Some regions have a lot more to choose from. There are always limitations too. Tropical plants do not survive the winters of New England. Apples and pears want more winter chill than they can get in San Diego.
Some flowers are better left in the garden rather than cut and brought in. Society garlic, Tulbaghia violacea, looks like it would be an ideal cut flower, with nice bare stems. The aroma suggests otherwise. It smells something like a strongly aromatic combination of onion and garlic. Even in the garden, it might be a good idea to keep it at a distance. Deer and rabbits do not mess with it.
Dracaena palm, Cordyline australis, is not a palm at all. It is more closely related to yuccas. (Incidentally, a few yuccas are also inaccurately known as palms as well, but that is another story.) The simple specie that grows taller than a two story house is rare nowadays. It develops a high branched canopy of evergreen olive drab foliage. The three inch wide leaves are about three feet long.
Tony Tomeo 