Family: Scrophulariaceae
Species: Buddleja davidii Franch.
Common Name
David’s Buddleja, Butterfly Bush English: Butterfly-bush, Summer lilac Deutsch: Schmetterlingsflieder
Etymology
The genus name honours the English pastor Adam Buddle (1660–1715), a physician and amateur botanist. The species was named by the French botanist Adrien René Franchet (1834–1900) in honour of the Jesuit missionary Father David (1826–1900), a skilled naturalist and discoverer of numerous species.
Description
Asiatic – a plant of the Asian continent
A rustic, deciduous shrub that grows quickly, reaching up to 5 m in height. The opposite leaves are pointed and toothed, dark green on the upper side and white and tomentose underneath. The most striking feature of Buddleja is undoubtedly its flowers: hermaphroditic, scented, numerous, and clustered in dense cylindrical panicles measuring 20–50 cm in length. Each flower, borne on a short peduncle, can range in colour from pink to dark purple or from white to lilac; it has the shape of a hairy, bell-shaped calyx. The fruit is a capsule encased by the calyx and the persistent corolla, containing numerous fusiform, winged seeds that remain on the plant for most of the winter.
Notes and Curiosities
Originally from China, this plant was introduced into Europe in 1893. It is often used to decorate parks and gardens for the colour of its flowers, its delicate scent that attracts butterflies, and its resistance to cold and drought. However, it has soon escaped cultivation and is becoming invasive. It easily adapts to any type of soil, preferring calcareous soil, and it does not fear frost, tolerating temperatures down to -15°C. It grows rapidly due to its numerous underground stolons (through which it reproduces vegetatively) and produces a vast quantity of seeds (up to 3 million per plant) dispersed far by the wind; watercourses can also carry them.
It is included in the black list of non-native plant species of Lombardy and among the exotic species that are invasive and harmful to biodiversity conservation, because in nature—on degraded, arid, or well-drained soils—it forms dense populations that displace indigenous vegetation, altering the natural landscape’s appearance. Although it can withstand large temperature variations, very high temperatures, and water shortages can limit its presence.
In order not to lose the obvious advantages of adaptability, ease of cultivation, color, and—last but not least—the allure Buddleja holds for butterflies, numerous sterile hybrids of Buddleja davidii have been developed in recent years. Some do not form seeds at all, while others produce sterile or very heavy seeds that the wind cannot easily scatter.