Pterostyrax corymbosa

The Pterostyrax corymbosus (synonym Halesia corymbosa) is a decorative and hardy small tree or large Asian bush that should find its way into our gardens. This cousin of the Styrax also offers a fragrant spring flowering and beautiful autumn colours. Its clusters of pleasantly scented white flowers are followed by unique and decorative fruits in dry compositions, and its bark with cinnamon aromas can be used in potpourri. Hardy and disease-resistant, this beautiful plant deserves to be discovered.

Native to Japan and China, Pterostyrax corymbosus is a large bush in the styracaceae family, composed of trees and shrubs with aromatic resin. It is a small ornamental tree that prefers cool, humus-rich, non-calcareous soil. Its natural habitat is forested, and it is found in fairly moist areas, not far from watercourses, at altitudes ranging from 400 to 1600 m (1312 to 5249ft). In its native lands, it can grow up to 12 m (39ft) in height, but under our climate it will typically reach 2.50 m (8ft) or 3 m (10ft) in all directions. It will reach a maximum height of 5 m (16ft) under optimal conditions. Its growth is fairly rapid.

The habit of Pterostyrax corymbosus is generally rounded if it has space, narrower when it grows in a thicket. It often forms a short trunk, or several small trunks, supporting a wide, regular and airy crown. In its early years, it resembles an erect bush. The deciduous foliage is composed of ovate leaves, strongly veined, measuring 6 to 14 cm (2 to 6in) in length and 4 to 8 cm (2 to 3in) in width, with finely toothed edges and hairy when young. They are a fairly light green color. Before falling, they turn a beautiful bright yellow, visible from afar in the garden.

Sometimes it takes 4 or 5 years to enjoy the first flowering on well-established plants. In May-June, on one-year-old branches, hanging panicles of clusters about ten cm long appear, composed of numerous small fragrant white flowers. Each flower, measuring 1 cm (1in) in length, has a bell-shaped corolla that widens into 5 tapering lobes, with protruding stamens. The bush covered in white flowers offers a magnificent spectacle. This fragrant flowering, visited by pollinating insects, gives way to ovoid and dry fruits, with 5 prominent veins, measuring 1 to 2 cm (1in) in length. These drupes, covered with a gray-yellow velvet and with a conical projection, are quite decorative. This Pterostyrax has excellent hardiness, around -20°C (1°F).

Pterostyrax corymbosus likes soils rich in humus, neutral to very acidic, cool and light, a soil that is suitable for hydrangeas and rhododendrons. Plant it isolated, near a pathway or not far from the house to fully enjoy its fragrance and beautiful autumn colours. It will also find its place in a flowered hedge or in a large shrub bed. This small tree's delicacy also pairs perfectly with the simplicity of an ornamental bramble Rubus Olympic Double. Consider also deciduous euonymus (Euonymus Red Cascade, alatus) and witch hazels (Arnold Promise) to accompany its golden foliage in autumn. For decorating its base, you can, for example, use small variegated euonymus shrubs (Emerald Gaiety) and Naples or coum cyclamens.