Pittosporums

Pittosporum crassifolium blossom

Pittosporums are a large group of tough and adaptable evergreen shrubs or smallish trees native to subtropical and tropical Australasia, Africa, and Asia and grown in warm temperate climates throughout the world.  Most are fairly fast growing in full sun to part shade in any reasonably fertile soil with decent drainage and little to moderate moisture.  All bear small, fragrant, late spring or summer flowers in clusters at the ends of stems followed by conspicuous fruits with bright orange seeds. Several species and quite a few cultivars are commonly found in the nursery trade.

Pittosporum tobira is a rounded shrub to 15 feet tall and ten feet wide with leathery, dark green leaves, shiny on the uppersides and slightly turned under along the edges. The small, intensely fragrant flowers open white and soon turn creamy yellow. Native to Japan, Korea, and parts of China, this densely foliaged plant makes a fine hedge or privacy screen and is attractive with lower branches pruned up as a small specimen tree.  The cultivar ‘Wheeler’s Dwarf’ is two to three feet tall and four to five feet wide. ‘Variegata’, three to five feet tall and wide, has variegated leaves.

Pittosporum crassifolium ‘Variegatum’

Pittosporum tenuifolium, 25 to 30 feet tall and 15 to 20 feet wide, bears glossy, medium green, slightly wavy leaves on distinctive nearly black stems that accentuate the upright form of this attractive shrub.  The flowers are dark reddish purple.  Native to New Zealand, it is tolerant of salt spray, dry soils, and shade.  Many cultivars are in the trade, including ‘Golf Ball’, an amusingly rounded shrub three to four feet tall and wide with exceptionally dense foliage, and ‘Marjorie Channon’, eight feet tall and wide with creamy white margins on the leaves.

 Pittosporum eugenioides is a shrubby tree to 30 feet tall and 15 to 20 feet wide with wavy-edged, glossy green leaves and yellow flowers. Native to New Zealand, it makes a good, fairly fast-growing screen. It needs part shade away from the coast.

Pittosporum phillyraeoides, slow growing to 20 feet tall and 15 feet wide, has narrow, dark green, willow-like leaves and a weeping habit. Native to coastal northwestern Australia, it is tolerant of considerable heat and dryness.

Attesting to the wide adaptability of most plants in the genus, at least two pittosporums have become weedy pests in Australia, while others occasionally have been described as “garden thugs.” All probably should be watched for any inclination to take over or escape. The worst offender is Pittosporum undulatum, commonly known as Victorian box, which is highly invasive in Australia and South Africa.  P. crassifolium, an attractive gray-leaved shrub with maroon flowers and several named cultivars in the trade, has also shown invasive tendencies in Australia.

I should put in a good word for Pittosporum tobira in this regard, three large shrubs of which graced the wooded portion of my lot when I settled here almost forty years ago.  Mature then, they are elder statesmen now. They make a fearsome mess in winter with their sticky discarded seeds, but these are loved by birds and not once have I seen new plants appear.

Arbutus

Arbutus unedo 'Elfin King' (Strawberry Tree) with fruit.

Arbutus unedo ‘Elfin King’ with fruit.

With evergreen, leathery, dark green leaves, showy clusters of tiny white spring flowers, small red berries in fall, and red-brown peeling bark, Arbutus menziesii is a signature tree of western North America.  Native to coastal evergreen forests from southern British Columbia to California, the western slopes of the Sierra Nevada, and the eastern slopes of the Coast Ranges, this tree has long been considered too difficult for most cultivated landscapes.  Commonly known as Pacific madrone, A. menziesii is available in small containers mostly from specialty nurseries and at native plant sales.

For best results, Arbutus menziesii should be set out in its permanent spot when the seedling is a foot or so tall.  Excellent drainage is essential.  Young trees seem to prefer the filtered shade of evergreen trees, but may not establish in full shade. They thrive in full sun along the coast and inland at higher elevations.  Water only to establish and do not fertilize.  Water and fertilizer will promote growth but make this plant more susceptible to disease.  Usually slow-growing to anywhere from fifteen to fifty feet tall, trees may reach over 100 feet at great age.

Arbutus unedo (Strawberry Tree) by gravel pathway with ornamental grasses in David Fross waterwise sustainable garden

Arbutus unedo (strawberry tree) by gravel pathway with ornamental grasses

Arbutus unedo, strawberry tree, is native to the Mediterranean Basin and parts of western Europe.  With evergreen, leathery, dark green leaves, drooping clusters of small rosy white flowers, largish red fruits, and peeling reddish brown bark, strawberry tree is similar in many ways to Pacific madrone but much more tolerant of garden conditions. It grows in sun or shade and most soils and accepts some summer irrigation as long as drainage is adequate.  Where content, it can reach fifteen to thirty feet tall and almost as wide.

Cultivated varieties of Arbutus unedo are common in the nursery trade. ‘Elfin King’ is a compact shrub with denser branching and somewhat slower growth than the species. ‘Compacta’ is said to be similar, reaching six to ten feet tall and wide at maturity.

Arbutus ‘Marina’ is a fairly large tree (forty feet tall and thirty feet wide at maturity) that looks enticingly small in fifteen-gallon containers.  You will see it planted five feet from a building wall in new landscapes.  In such situations you can be sure it will outgrow its allotted space and over time will require quite brutal pruning or removal.

‘Marina’ is often promoted as a garden-tolerant equivalent of Arbutus menziesii, and it is somewhat more accepting of typical garden conditions – a bit of summer water, less than perfect drainage, and clay soils.  But it won’t take as much abuse as commonly assumed, especially excess irrigation or poorly drained soil.  It is also best planted in a spot that can feature rather than fight the shedding of bark, fruits, and large leaves, which, as with most strawberry trees, is pretty much continuous.

California buckeye

Aesculus californica, California buckeye tree in winter with bare branches at East Bay Regional Parks Botanic Garden, Berkeley.

Aesculus californica, in winter, at East Bay Regional Parks Botanic Garden, Berkeley.

California buckeye (Aesculus californica) puts on a bold and fascinating seasonal show.

In late winter bright apple-green new leaves burst forth at branch ends and rapidly unfold, quite suddenly claiming the stage among the darker greens of evergreen oaks, bays, and pines.  In spring to early summer showy spikelike clusters of lightly fragrant creamy white flowers are held gracefully upright above the leaves.  The large polished-brown seeds peeking through leathery, pear-shaped pods are highly decorative on silvery gray branches in fall.

Flower head of Aesculus californica - California buckeye tree

Aesculus californica flowers

Native to much of California on dry slopes, in canyons, and along waterways, California buckeye needs no summer irrigation once established, though trees will respond to heat and drought by dropping leaves.  It’s hard to be fully prepared for the large palmate leaves to turn pale yellow, droop sadly on the tree, and drop in what seems to be high summer.  Occasional deep soakings may help keep leaves on the tree a little longer in coastal areas.

California buckeye grows 15 to 35 feet tall and spreads more widely.  Form is best in sun, where trees develop into a living sculpture of multiple or low-branching trunks, symmetrically outstretched branches, and a delicate tracery of small branchlets.  Trees thrive in part shade but may be awkwardly shaped and rangy. Good drainage is appreciated.  Deer will browse the leaves.

Aesculus californica-California Buckeye in fall fruit

Aesculus californica fruit

In years of normal rainfall, the heavy seeds sprout and establish themselves pretty much where they fall, unless they roll downhill or are carried away by water.  They can be moved before the large whitish root finds its way into the soil.  Plant with the root covered by soil and the seed at least partially exposed.  Keep soil lightly moist until new growth is decisively underway.  Water for the first year or two, especially if winters are dry.

California Native Redbud Tree

holt_433-177.tifI hear from long-time residents of Amador County, California, that our native redbud (Cercis occidentalis syn C. orbiculata ) is not found anywhere in that county except where planted.  To me, this is a fascinating mystery, as it is commonly reported by reliable sources as occurring in the wild in that part of the state.  Some have suggested it may be the soils, that redbud requires “ultramafic”  (basic) soils, even serpentine, that are not common in Amador County.  If you live in that part of the world, please let us know if you have seen this special plant in the wild and exactly where. Continue reading