Lonicera japonica Thunb. ex Murray (China, Japan) – A very rare but increasing escape from cultivation, locally becoming naturalised. Known at least since 1984 from a disused railway yard in Schaarbeek (Brussel) but now probably gone after infrastructural works. Discovered in abundance in 2004 at the ruins of the Sint-Baafs abbey in Gent and regularly confirmed (for instance in 2010). Scattered individuals also persist in the surroundings (for instance on an old brick quay of canal Achtervisserij). Known since 2008 from an old coalmine heap in Damprémy (Charleroi). In 2010 discovered by a disused railway track in Evergem (N-Gent). In 2011 also observed as an aggressive coloniser in scrub along river Leie in Bissegem (see photo) and in coastal dunes in Koksijde. Probably overlooked elsewhere.
Lonicera japonica is rather reminiscent of native L. periclymenum and might pass unrecorded as a poor-flowered specimen of the latter. However, even non-flowering plants are readily distinguished: Lonicera japonica has densely and shortly pubescent twigs whereas L. periclymenum has very sparsely glandular hairy twigs. In fruit both are very distinct: berries are black (and evidently per two) in Lonicera japonica and red (and numerous) in L. periclymenum.
Lonicera japonica is a reputed environmental weed in many countries, especially in warm-temperate regions (see for instance Schierenbeck 2004). In parts of Central-Europe (including Switserland) it is on the Black List (see also Nobis 2008). Lonicera japonica is potentially invasive in Belgium as well (http://ias.biodiversity.be/species/show/63).
|
|
|
Selected literature
Nobis M. (2008) Invasive Neophyten auch im Wald? Wald Holz 89(8): 46-49.
Schierenbeck K.A. (2004) Japanese honeysuckle (Lonicera japonica) as an invasive species: history, ecology and context. Crit. Rev. Pl. Sc. 23(5): 391-400.