OSMANTHUS. Sweet olive. China, Japan, Caucasus. Anyone who has grown up in California should know the osmanthus at least by sight, though perhaps not by name. The following include some of the popular kinds and some almost untried in California. These are evergreen shrubs of the olive family, with sturdy, limber stems, attractive pale bark, and leathery, often glossy, paired leaves. Often the leaves are conspicuously toothed, even spiny. Some species are showy in bloom, though the flowers are generally small and presented in smallish clusters; many are fragrant. They have blue to purple fruits which are sometimes decorative.
The osmanthus respond well to almost any style of pruning and make excellent screens and hedges. They thrive in sun or light shade, in most soils and with moderate watering. The following are hardy to 15oF. or less, except as noted.
armatus (?). The plant in question may actually be O. yunnanensis, for the two are quite similar. It grows strongly erect, probably to 10’ or more. Bark is pale and smooth. Neatly paired along the stems are rather wicked-looking leaves, broadly oval in general outline but strongly indented between stout spines. The leaves are deep green above, paler beneath, and bronze-tinted in new growth. Small, fragrant, cream-colored flowers are borne in paired clusters along the stems in summer, followed by purple fruits a little over 1/2" long.
x burkwoodii (Osmarea x burkwoodii). For those who knew it as Osmarea, the change came with the reclassification of one parent (O. decorus, below) from the genus Phillyrea to Osmanthus. The other parent, which this plant more resembles, is O. delavayi (also described below). It is a bushy, rather slender stemmed shrub. It has spreading branches, neatly set with dark, finely toothed 1-1½” leaves. The flowers are white, tinged with green, and fragrant. It always has the clean, bright look that gardeners achieve only through endless pampering of other shrubs.
decorus (Phillyrea decora). One of the most attractive foliage shrubs to invade the California market in several years (would that there were a little more interest in foliage shrubs). This is a round, well-branched shrub, growing 6-10’ (or more) high. It has rather stiff, straight pointed-oval leaves up to 5" long. The leaves are quite smooth and deep green above, with lighter midribs and a yellow-green lower surface. It is spring-blooming, displaying abundant, fragrant white flowers. The fruits are large, nearly black and showy.
delavayi. China. This species has been on the fringes of California horticulture for many years, mysteriously unappreciated. It is a spreading shrub, usually around 6’ tall at maturity, with a clean, bright appearance. Dark, shiny 1" leaves are closely set along the slender stems. In spring it bears clusters of tubular white, fragrant blossoms all along the younger stems. Sun or light shade, most soils, moderate watering.
x fortunei ‘San Jose’. A hybrid between O. fragrans and O. heterophyllus, both described below. It grows usually 6-10’ tall, with many branches held nearly erect. It has broadly oval, conspicuously toothed leaves up to 4" long, not so thick and rigid as those of O. heterophyllus. They are quite shiny on their upper surface and tinged with bronze to purple in new growth. Sweetly fragrant white flowers decorate the plant in late summer.
fragrans. Sweet olive. Himalayas to Japan. This species, in its typical form, and O. heterophyllus, described below, are the most used and abused of the genus. However, there is plenty still to explore here. This is an exceedingly variable shrub–or even small tree–growing from 8’ to over 30’ high. It has bright green, glossy leaves up to 6" long, broadly to narrowly pointed-oval in outline. Small clusters of sweetly fragrant, usually cream-colored flowers, each under 1/2" long, are borne in the leaf axils in summer. The forma aurantiacus has longer, narrower and more deeply veined leaves, more loosely spaced along the stems than usual. In late summer and fall, it is decorated by flowers which are equally fragrant but orange in color and quite showy. ‘Nanjing’s Beauty’ is a recent arrival from China, received from Piroche Plants. This is a bushy selection, growing about 12’ tall. The leaves are dark, relatively narrow and up to 6" long. Established plants carry exceptional quantities of creamy flowers from April to October. ‘Thunbergii’ is a stout, bushy plant, around 10’ high. It has equally dark but broader, deeply veined leaves, with a lacquered surface and conspicuous teeth. New shoots are dramatically painted in bronze to purple shades. Its flowers are typical of the species. Hardy to around 15oF, though the new shoots which appear through the winter may be badly burned by hard frosts.
heterophyllus. Holly olive. The best-known of the genus, with many cultivars. It a well-branched shrub, usually upright-oval in form, growing as much as 15’ high in the larger selections. It has thick, usually sharply toothed leaves, from 1" to 3" in length. The flowers are white and fragrant, though not very conspicuous. ‘Ilicifolius’ is listed as a synonym for the species itself, but there is a tangible, distinct cultivar here under that name. It is a bushy shrub with 2" deep green, shiny leaves, bronze in new growth. ‘Purpureus’ is a little more open in growth, with smaller dark, glossy leaves. Younger leaves and stems are heavily shaded with reddish purple. ‘Variegatus’ is much more congested and somewhat irregular in form. It has smaller, closely packed leaves with creamy yellow margins. Hardy to 10oF. or less.