Of all the popular pittosporums in Western landscapes nowadays, the karo, Pittosporum crassifolium, is certainly not one of the most familiar. It might have been one of the earliest to have been popularized here though. Because of its resiliency to coastal climates, it was a common hedge in San Francisco during the Victorian Period. With minimal watering, it did well farther inland too.
Karo are nice fluffy evergreen shrubs that can get fifteen feet tall. They excel both as informal screens and refined hedges, and can be staked as small trees on single straight trunks. Alternatively, lower growth of big shrubby specimens can be pruned up to expose a few delightfully sculptural trunks. ‘Compactum’ is a densely foliated mounding cultivar that might stay less than three feet tall.
The Latin name, Pittosporum crassifolium, is quite descriptive. The literal translation is “sticky-seed thick-leaf”. The two or three inch long leaves are not really thick, but their slightly grayish upper surfaces and more grayish tomentous (fuzzy) undersides make them seem almost succulent. Small and round seed pods eventually split open to reveal dark seed glued together with sticky resin.
Ah, something vintage! Remember Hollywood juniper, Juniperus chinensis ‘Kaizuka’ (or ‘Torulosa’) flanking big two-car garage doors of mid century modern homes? Those that are still around after half a century are big and strikingly sculptural, like miniature Monterey cypress for home gardens. They get about fifteen feet tall and ten feet wide, but have potential to get significantly larger.
Hollywood juniper is an old classic that is still reasonably available in some nurseries. Their densely foliated stems twist and turn picturesquely upward, typically leaning one way or another toward sunlight or away from prevailing wind. Some say they look like frozen green flames. Their gnarly trunks and flaking bark can be exposed as they grow tall enough for low growth to be pruned away.
Because of their very irregular branch structure, Hollywood juniper is more adaptable to free-formed pruning than the presently trendy junipers with strictly upright or conical form. They must never be shorn, but do not mind if obtrusive limbs get pruned back to the main trunks. Therefore, they are actually more adaptable to smaller modern gardens than some modern cultivars of juniper are.
A surplus of common names seems to be a common theme for many plants that we thought we knew the names of. The simple Pittosporum tobira, which might be known here by its Latin name, might instead be known as mock orange, Australian laurel, Japanese pittosporum, and Japanese cheesewood. Its native range is about as diverse, including Greece, Japan, Korea and China.
Back in the 1990s, the compact cultivar known as ‘Wheeler’s Dwarf’ was common enough to be as cliché as tam junipers were in the 1950s. There are actually a few other dwarf and variegated cultivars that do not share that reputation. Most are low, dense and mounding. ‘Variegata’, although not a compact dwarf, grows slower and stays smaller than the unvariegated straight species.
Otherwise, Pittosporum tobira gets about ten feet tall and wide. It can eventually get significantly taller, especially if lower growth is pruned away to expose the sculptural trunks within. If shorn as a hedge, it should not be shorn so frequently that the dense foliage is always tattered. Leaves are delightfully glossy and convex. Small trusses of modest pale white flowers are sometimes fragrant.
Here on the West Coast, privets had traditionally functioned like hollies had in the East. They are conducive to shearing into the big formal hedges that were popular during the Victorian period. Since then, as gardening space became more limited, the common glossy privet became less popular than the more compact and complaisant waxleaf privet, Ligustrum japonicum ‘Texanum’.
Since it does not get much higher than ten feet, and typically stays less than eight feet tall, waxleaf privet is proportionate to urban gardening. As a formal hedge, it can be shorn to stay less than two feet from front to back, although taller hedges look better if allowed to get bulkier. As an unshorn informal screen, it should not get much broader than six feet, with an appealingly billowy form.
Foliage is evergreen and remarkably glossy, sort of like that of holly, but without the prickles. Regularly shorn hedges should not bloom, but might produce a few trusses of tiny white flowers inside of the shorn surfaces. In sunny situations, unshorn glossy privet blooms profusely enough to be mildly fragrant in spring. Bloom sometimes produces floppy clusters of tiny but messy black berries.
‘Shrubbery’ sounds so unflattering for a pine; but mugo pine, Pinus mugo, is not really much of a tree. The tallest trees do not reach eaves. Most old trees are only a few feet tall and about twice as broad, with strictly rounded form, and dense forest green foliage. The stout paired needles are only about one or two inches long. The plump cones, which are rarely seen, are not much longer.
Although very rare in other types of landscapes, and originally from the Austrian and Italian Alps, mugo pine is one of the most popular and traditional features in Japanese gardens. Even though it grows very slowly, it should have enough room to do so without competing with other more aggressive plants that might overwhelm it. It should neither be shorn nor pruned back too aggressively.
As a shorn evergreen hedge or simple shorn shrubbery, photinia, Photinia X fraseri, produces handsomely glossy bronzy red foliage without bloom. It is best if shorn as weather warms at the end of winter, and then allowed to grow out for a while. It can be shorn again through summer as bronzy foliage fades to green, but should not be shorn so often that it is always deprived of red foliage.
Without regular shearing, photinia becomes a small tree or large shrub. Trees can either be staked on single trunks, or allowed to develop multiple trunks. New growth in spring is not as vigorous as it would be in response to shearing, so is not as colorful. Domed trusses of tiny white flowers bloom about as soon as new foliage appears. The floral fragrance can be objectionable to some.
Only the biggest and oldest trees reach high voltage cables. Most stay less than fifteen feet tall and broad. Hedges can be kept less than six feet tall, and ideally, should be kept less than half as deep (from front to back). Photinia can grow rather well while young, but then grows slower as it matures. Partial shade or a lack of water through summer compromise foliar color and density.
Those of us who appreciate olive trees for their fruit production or distinctively gnarly trunks probably would not understand the popularity of the Little Ollie olive, Olea europaea ‘Little Ollie’. Not only is is completely fruitless, but it lacks sculptural trunks and limbs. It is instead a short and and shrubby plant that gets only about three or four feet tall, with very dense grayish green foliage. Only the narrow evergreen leaves are recognizable as those of an olive tree.
Little Ollie olive behaves something like boxwood, and does not grow much faster. It can even be shorn as a hedge or topiary. It is quite resilient to heat and harsh exposure, and once established, it does not need much water. Because it is so compact, and has such resilient roots, it is popularly grown in large urns or planters. The grayish foliage is a nice backdrop for more colorful annuals and flowering perennials.
Between New England and the Pacific Northwest, the boulevard cypress, Chamaecyparis pisifera ‘Cyano-viridis’, is classified as a small tree, even though it gets no bigger than large shrubbery. Locally, only very mature specimens reach the eaves, without getting much more than half as broad. Trunks and limbs remain concealed by fluffy evergreen foliage. Warm and dry air limit growth.
The handsome foliage is strikingly silvery blue, comparable to that of Colorado blue spruce or blue Arizona cypress, but with a surprisingly soft texture. It is really quite distinct from other evergreens, even other closely related chamaecyparis.
Boulevard cypress prefers cooler climates, so does well locally in light shade sheltered from wind. During warm weather, it can get roasted if too exposed. Although it does not require much water when mature, it is happiest if watered somewhat regularly.
The first half of the name sound appealing enough. The second half, not so much. Do the seeds grow into snails? Do they just look like snails? Not many have seen them. Tiny pale white flowers that are supposed to bloom in spring, as well as small black berries that develop after bloom, are rare. Laurel-leaf snailseed, Cocculus laurifolius, is grown just for its glossy evergreen foliage.
The foliage superficially resembles that of common privets. Upon closer inspection, the leaves are somewhat elongated, and outfitted with distinct marginal veins flanking the midveins. As stems that become heavy with lush foliage lean over, vigorously vertical stems fill in the space, until they too arch over as they become fluffy with foliage. Mature trees might get twenty feet high and wide.
Because of its complaisant roots and tolerance of partial shade, laurel-leaf snailseed is popularly installed as a foundation plant (at the foundation of a home) but then obscures windows as it gets too big and awkward. Its arching branch structured does not do well with formal shearing. It works much better as an informal screen in the background, or as small tree with multiple trunks.
With indiscriminate pruning, glossy abelia, Abelia X grandiflora, will never develop its natural form, with elegantly long and thin stems that arch gracefully outward. Sadly, almost all get shorn into tight shrubbery or hedges that rarely bloom. If only old stems get selectively pruned out as they get replaced by fresh new stems, mature shrubs can get eight feet tall and twelve feet wide.
Against their bronzy green foliage, the tiny pale pink flowers that bloom all summer have a rustic appeal. In abundance, they can be slightly fragrant. The tiny leaves are not much more than an inch long. Vigorous young canes that shoot nearly straight out from the roots slowly bend from the weight of their bloom and foliage as they mature.
Partial shade is not a problem for glossy abelia, but will inhibit bloom somewhat. Young plants want to be watered regularly. Old plants are not nearly so demanding, and can survive with notably less water. If alternating canes is too much work to restore old and neglected plants, all stems can be cut back to the ground at the end of winter. New growth develops quickly.