Stewartia pteropetiolata

Stewartia pteropetiolata is an Asian bush related to camellias, mainly known by collectors because it is very rare in cultivation. It has evergreen, dark green and glossy foliage. This dark vegetation enhances its white spring flowers. The bush has an upright habit with layered growth. It is not very hardy and requires acidic, moist to wet soil. It will only thrive in open ground in the mildest areas.

Stewartia belongs to the small family of Theaceae, mainly known for camellias, with the most famous non-ornamental representative being the Tea Plant (C. sinensis). There are about ten species of Stewartia according to classifications, almost all of them native to Asia, except for two found naturally in North America.
Stewartia pteropetiolata is native to Yunnan (a province in southern China with a predominantly subtropical climate) and Vietnam, and it is frost-sensitive from around -5°C to -6°C. In its natural habitats, it forms a large bush of 6 m or more in height, reaching up to 15 m as a tree, with a fairly straight trunk covered with a beautiful fissured grey bark. It produces rather inconspicuous white flowers that turn yellow as they wither and fall to the ground, while sometimes they remain on the plant and develop into red fruits. It is found growing in forests in mountainous areas, at altitudes ranging from 1200 to 2600 m. It was discovered by Irishman Augustine Henry, a passionate botanist and great provider of seeds and plant samples from the Kew Gardens botanical garden in London, and introduced to Europe in 1912.
In the few areas where it can be grown in open ground, it will form an upright bush with slow growth. With age, the plant will reach 6 m in height and 4 m in width. Its main characteristic is its evergreen foliage, which has led some botanists to classify it in a separate genus (Hartia sinensis). Furthermore, the leaves are carried on curiously winged petioles, hence its specific name (pteron = wing in Greek). The leaf blade has an elliptical shape and measures from 6 to 13 cm in length and 2.5 to 5 cm in width. The petiole is short, 1 to 1.5 cm long, and equipped with a 3 mm wide wing. The leaves are dark green and their surface is glossy, creating a pleasant contrast with the young branches which are yellowish at first, then reddish-purple before turning grey when mature. The dark vegetation allows for a better appreciation of the flowering, which would otherwise be relatively inconspicuous. The white flowers, resembling those of some camellias (but smaller), only measure 3 cm in diameter. They are solitary and bloom in April and May. The centre of the corolla is occupied by numerous stamens whose bases are fused, forming a sort of tube. Their dark yellow tips give relief to the single flower, resting on oval, reddish-purple sepals. When fertilised, the flower produces an ovoid capsule fruit, 1.5 to 2 cm long and 1 to 1.5 cm wide, composed of five small lobes.

This Stewartia will grow in very mild oceanic climates, such as the one prevailing in Cornwall, England and elsewhere in Europe, it is also found along Lake Maggiore, which has a particular microclimate. It must be recognised that the species is not the most attractive in the genus, and it will mainly interest enthusiasts and collectors. A Eucryphia x intermedia Rostrevor will offer a similar-looking flowering but with slightly larger and more abundant flowers, as well as better hardiness. However, Stewartia pteropetiolata has the advantage of being rarer and exuding a certain romantic charm, coupled with an exotic appearance. You can integrate it into a bed alongside Embothrium coccineum, or Chilean Fire Tree, another curiosity with more or less evergreen green foliage and exceptionally flamboyant red flowering.