Shrub of erect habit, to 3 m. Twigs glabrous, brownish, 4-angled, with raised lenticels; pith lamellate. Leaves ovate, 5–8 × 2–4 cm, acuminate, base rounded, glabrous, irregularly serrate or more often entire; petiole 4–8 mm. Flowers not scented, carried singly or sometimes in pairs at each leaf-scar. Calyx-lobes broad-ovate. Corolla bright yellow, 3 cm wide, with narrowly oblong lobes. Fruit smooth, ovoid, long-beaked. (Bean 1981).
Distribution Albania Bosnia and Herzegovina Bulgaria Croatia Kosovo North Macedonia Serbia
Habitat Mountain forests, rocky places.
USDA Hardiness Zone 4-5
RHS Hardiness Rating H7
Conservation status Least concern (LC)
Forsythia europaea is a classic Ice Age relic species, surviving in an area comparable with that of the European Horse Chestnut Aesculus hippocastanum. Within these bounds, it remains common enough to be assessed by the IUCN as of Least Concern (IUCN 2020). The most recent genetic analysis (Ha et al. 2018) suggests that the species diverged from its nearest Chinese allies between 2 and 10 million years ago, before the first Eurasian glaciation and a time when a warmer climate would have made most of northern Europe and Asia suitable for the spread of such plants. (An earlier analysis (Kim 1999) had suggested a much more recent severance from the Chinese Forsythias, less than half a million years ago, but this conclusion had been hard to square with the geological evidence).
Forsythia europaea was discovered as recently as 1897 by the Italian botanist Antonio Baldacci, at at time when its Chinese allies were just gaining popularity in the west as garden plants. Baldacci sent seed to the Royal Botanic Gardens, Kew in 1899, and the species was rapidly and efficiently distributed among the leading collections and nurseries of the time, reaching America the following year as seeds sent to the Arnold Arboretum by Arthur Kilpin Bulley of Ness in Cheshire (Arnold Arboretum 2018), whose garden is now the Ness Botanic Garden.
This is one of the last Forsythia species to flower in spring (Bean 1981) and the blooms, carried mostly singly at each leaf-scar, form a less spectacular display than that of today’s familiar garden hybrids; the habit is also often described as ungainly. It is slightly hardier than any of the Chinese species, and was first crossed at the Arnold Arboretum in 1935 with F. ovata by Karl Sax and Haig Derman with the aim of producing a super-hardy hybrid (Arnold Arboretum 2018). Along with F. ovata it was the only species considered reliably hardy across Poland in the 1950s (Suszka 1959), and it is still grown at the Linnaean Gardens of Uppsala in southern Sweden (Royal Botanic Garden Edinburgh 2022). It is now a rare species, confined to a few specialist collections, but will be represented in the UK’s new National Collection of Forsythias at Sculpture by the Lakes in Dorset by material from the Royal Botanic Gardens, Kew (M. Gudgeon pers. comm.).