Hopbush

Hopbush makes a nice small tree.

Johnny jump up and jumping cholla have no more than amusing names in common with hopbush, Dodonea viscosa. Neither a dangerous cactus nor a docile annual, hopbush is an elegantly upright and evergreen shrub. It is very popular for both informal and formally shorn hedging. With pruning, it can become a small tree with handsomely furrowed bark.

Hopbush has potential to get about as tall as a two story house, particularly with pruning for tree form. Conversely, with only occasional pruning for hedge form, it is just as happy to stay just six feet tall. Trees with single and straight trunks fit nicely into narrow spaces. Trees with a few irregular trunks that lean outwardly are more sculptural for larger areas.

The narrow evergreen leaves are about two or three inches long, with light bronzy color. ‘Purpurea’ has purplish bronze color, but does not grow as vigorously. Most hopbush are female, and generate interestingly papery seed. Bloom and seed production are variable though, and some specimens become male. Roots should be complaisant with concrete.

African Daisy

Modern African daisies are surprisingly colorful.

Only a few decades ago, the only familiar African daisies, Osteospermum spp., were the sprawling and often sparsely branched ‘freeway daisies’ with blue-eyed white or rarely light purple flowers. They made nice blooming ground cover that could be planted in drifts for a bit of color among the deep green of Algerian ivy on expansive freeway embankments.

Modern varieties are shrubbier perennials with more profuse bloom of white, cream, pink, purple, pale yellow or pale orange flowers, mostly with blue or purple centers. Some yellow flowers have yellow or cream centers. Some of the fancy types have spooned petals like some types of cosmos or chrysanthemums. After the primary bloom phase in spring, a few sporadic flowers may continue to bloom through summer until the secondary light bloom phase late in summer. However, the old fashioned ‘freeway daisy’ types do not always display a second bloom phase. Varieties with variegated foliage are still rather rare.

Even though African daisies can survive in inferior soil with minimal watering, they perform best with good soil and regular watering. Plants in containers can not disperse their roots like they want to, so are are more dependent on regular watering. Fertilizer prolongs bloom.

Tanoak

Tanoak is rare within refined landscapes.

Its plump and inch-long acorns are misleading. Tanoak, Notholithocarpus densiflorus, is not actually an oak. Otherwise, it would be a species of Quercus. Regardless, its wood is potentially as practical for furniture and flooring as wood of other oaks. It also works very well as firewood. Historically, tanoak bark was useful for tanning leather, hence its name.

Although native and somewhat common in some coastal forests, tanoak is almost never a choice for intentional planting. Those that inhabit home gardens likely either grew from acorns, or were there prior to development of the landscapes. Young trees can grow fast to more than forty feet tall, typically with conical form. Mature trees might get twice as tall.

Tall trunks of tanoak are elegantly upright, and eventually develop lofty branch structure. Their gray or brownish bark is handsomely furrowed. The somewhat leathery evergreen foliage produces potentially objectionable tomentum. The dentate leaves are two to four inches long. Sadly, tanoak is very susceptible to Sudden Oak Death Syndrome (SODS).

Calla

Few flowers are as elegant as callas.

If only it did not like such regular watering, the common white calla, Zantedeschia aethiopica, would be quite a sustainable perennial. Once established, it can be difficult to get rid of, particularly in well watered gardens. Even unwatered plants that die to the ground through dry summer weather are merely dormant and waiting for rain to regenerate and bloom.

The remarkably elegant blooms stand about two or three feet tall, each with a single spathe loosely wrapped as a flaring cone around a spadix that supports the indistinguishable diminutive flowers. The bright white spathe is often more than four inches wide, and can be twice as wide in shade. The spadix is only about three or four inches long, and as yellow as Big Bird. The spongy dark green leaves are about a foot or two tall.

‘Green Goddess’ blooms with a longer and recurved spathe with a green tip and margins. Colorful callas are actually different specie. All parts of all types of callas are incidentally toxic.

Red Passion Flower Vine

Red is simpler but more colorful.

The mostly white and blue common passion flower likely remains the most popular. After all, it is the weirdest. Elaborate and disproportionate floral parts imply that it is of another planet. Red passion flower, Passiflora racemosa, although less peculiar, is perhaps a bit more colorful. Its brick red flowers bloom randomly for as long as weather remains warm. 

Flowers are about three or four inches wide. They develop in open racemes that seem to spread out somewhat evenly over the exterior of their foliage. Bloom is not profuse, but is somewhat continuous until autumn. Newer flowers replace older flowers within the same racemes. Leaves are as wide as their flowers, with three blunt lobes and axillary tendrils. 

The lushly evergreen foliage can get shabby through winter, or completely ruined by just mild frost. It regenerates vigorously though. Aggressive pruning as winter finishes delays bloom, but promotes vigorous growth. Vines can potentially reach more than twenty feet. Fruit is rare without manual pollination. Fruit flavor can be bland without tropical warmth.

Argyle Apple

Silvery foliage with fibrous brown bark.

Such silvery foliage provides a bold display on such a substantial tree. Most comparably silvery foliage is of smaller perennials or shrubbery, such as agaves or artemisias. Agyle apple, Eucalyptus cinerea, grows intimidatingly fast to nearly thirty feet tall and almost as wide. Although shorter than most other eucalypti, it can get a hundred feet tall in the wild. 

Paired juvenile leaves of young trees are circular and sessile (clinging directly to stems, without petioles). Unpaired adult leaves are lanceolate and as silvery as juvenile leaves. Coppicing or pollarding force juvenile growth and temporarily eliminate adult growth, but also ruin structural integrity. Trees subsequently rely on repetition of the same technique. 

Trunks and limbs can be disproportionately bulky, and create an illusion of a bigger tree. Irregular branch structure can be sculptural. Fibrous brown bark is handsomely furrowed. Juvenile foliage is a popular accessory to cut flowers. Adult foliage is likewise delightful. Incidentally, the Latin name of this species often transposes for Eucalyptus pulverulenta.

Snowball Bush

Even without the variety of color of hydrangea, these relatively delicate, crisp white flowers of snowball bush are quite elegant.

Like small, clear white hydrangea blooms, the round, three inch wide floral trusses of snowball bush,Viburnum opulus ‘Roseum’, are composed of many smaller flowers. Unlike hydrangeas that bloom after vegetative (stem and foliar) growth, snowball bush blooms early, so that as it finishes, deteriorating blooms will be obscured by soft green foliage before anyone notices. The distinctively lobed, three inch wide leaves get quite colorful in autumn. Snowball bush should not be shorn, but can instead be pruned aggressively while bare in winter. Older or obtrusively tall stems should be pruned to the ground where possible. Good sun exposure without too much reflected glare or heat promotes bloom and autumn foliar color. Mature plants can get ten feet tall and nearly as broad.

Pygmy Date Palm

Other date palms are significantly larger.

Canary Island date palm is the largest local palm. Pygmy date palm, Phoenix roebelenii, although a species of the same genus, is one of the more diminutive palms. It might take many years to grow ten feet tall, and may never get twice as tall. Its pinnately compound leaves are only about two to four feet long. Thin leaflets are about five to ten inches long. 

Such compact stature is a distinct advantage for some situations. With sufficient sunlight, pygmy date palm is a delightful houseplant. It is also appealing within atriums and cozily compact gardens. For those who appreciate the aesthetics but not the large size of most palms, pygmy date palm is a practical option. It actually resembles a common date palm. 

Like all date palms, a pygmy date palm surrounds its single terminal bud with nasty long spines, which are specialized proximal leaflets. These spines are painful to interact with while grooming and pruning deteriorated old leaves and floral trusses back to their trunk. Unlike most other palms, mature pygmy date palms are not very conducive to relocation.

Flannel Bush

Abundant golden blooms are really spectacular, but because of irritating foliar fuzz, flannel bush should be enjoyed from a distance.

There is no way to say it delicately. Flannel bush, Fremontodendron californicum, is not easy to work with. It grows rapidly and rampantly with awkward form to about ten feet high and broad, but then starts to deteriorate when only about twelve years old. It can deteriorate even sooner if well irrigated. The fuzz on the foliage and young stems is irritating to the skin, especially during warm weather, so is very uncomfortable to handle. Otherwise, for out of the way spots, flannel bush is a striking native plant with impressively abundant bright golden yellow bloom this time of year. Neglected plants that do not get pruned or watered seem to be happier and more colorful, and can get older and much larger.

Heath

Heath prefers rich and acidic soils.

For Scotland, various species and cultivars of heath, Erica, may be as common as lily of the Nile is here. It has become somewhat popular in the Pacific Northwest and the North Coast of California also. It is likely less popular locally because it prefers acidic soil, and cooler and moister climates. Here, it appreciates regular watering and shelter from wind.

Mature heath is generally less than five feet tall, with densely mounding form. Only a few rare species get significantly taller. Most popular cultivars stay lower. Some creep slowly over their ground without getting more than half a foot deep. Their small and very narrow leaves are no more than half of an inch long, and almost resemble small spruce needles. 

Even with such a fine texture, this evergreen foliage is delightfully woodsy. It is generally dark forest green. Some cultivars produce ruddy, yellow or gray new foliage in spring. Of these, some retain their rich foliar color through much of the year. Tiny heath flowers that bloom most abundantly through winter or spring are white, pink, red, or purplish.