Cotoneaster dammeri C.K. Schneider, Ill. Handb. Laubholzk. 1(5): 761, 1906.
Synonym: C. humifusus Duthie ex Veitch (erroneously asigned to Praeger by Clement & Foster 1994).
Section Alpigeni, series Radicantes
Origin: China (Hubei).
Presence in western Europe: Naturalized in Germany (Dickoré & Kasperek 2010) and Great Britain (Stace 2010). Furthermore recorded from France (pers. obs.), Luxembourg (seen by the author in LG!) and Scandinavia (Karlsson 2002).
Cultivation in Belgium and the Netherlands: “common” (De Koning & van den Broek 2009). In Central Europe Cotoneaster dammeri is perhaps not fully hardy (most of its leaves may fall in winter; see Klotz 1957).
Comparative taxonomy: Species accepted by both Dickoré & Kasperek (2010) and Flora of China (Lingdi & Brach 2003). A related species, Cotoneaster radicans Dammer ex C.K. Schneider (syn.: C. dammeri var. radicans (Dammer ex C.K. Schneider) C.K. Schneider), is merely included in C. dammeri by Dickoré & Kasperek l.c. but accepted as a variety of the latter by Lingdi & Brach l.c. and Klotz (1957). According to Fryer & Hylmö (2009) it is rather rare in cultivation and most plants belong to the sexual and variable Cotoneaster dammeri. Distinguishing features between both species are rather vague (compare for instance Klotz l.c., Lingdi & Brach l.c., Fryer & Hylmö l.c. and Stace 2010). Cotoneaster radicans usually has 3 (rarely 2 or 4) nutlets per berry (vs. usually 5, rarely 4 in C. dammeri) and smaller leaves (12-20 x 7-10 mm; versus 15-40 x 7-21 mm in C. dammeri) with less deeply impressed veins. Petiole and pedicel length (cf. Lingdi & Brach l.c.) are apparently less diagnostic (see Fryer & Hylmö l.c.).
Illustrations: Hylmö (1993), Grevtsova (1999), Roloff & Bärtels (2006), De Koning & van den Broek (2009), Fryer & Hylmö (2009), Stace (2010).
Although it is commonly cultivated since quite a long time Cotoneaster dammeri was probably not recorded in the wild in Belgium before 2007 when it was found on graves and paths in the Campo Santo cemetery in Gent (confirmed in 2010). In the past years it was repeatedly seen in a few, widely scattered localities: for instance on gravely soil by car boxes in Tessenderlo in 2010, on a calcareous talus slope of a canal in Moen in 2011 and on top of an old quay wall (canal Ieper-Comines) near Ieper, also in 2011. In most cases, Cotoneaster dammeri is found in small amounts, often even single individuals. It is not yet fully naturalized.
In Belgium, Cotoneaster dammeri mostly seems to grow on stony substrate (top of old walls, cracks in concrete, gravel), usually in full sun or half-shade. In Moen (nature reserve Vaarttaluds) a single plant grows on a sun-exposed, calcareous slope, forming an impressive ‘carpet tree’ ca. 6 m across (see also Dickoré & Kasperek 2010). In Franche Comté (France) Cotoneaster dammeri is - like C. horizontalis - an invasive species in similar habitats (see: http://conservatoire-botanique-fc.org/doc-flore-phytosociologie-cbnfc/sensibilisation/especes-invasives-de-franche-comte-les-cotoneasters-asiatiques/view).
Cotoneaster dammeri is a rather characteristic species, unlikely to be confused with other garden escapes (except perhaps C. radicans; see above). It is an evergreen, creeping (‘carpeting’) shrub, rooting at the nodes with leaves that are usually rounded at apex, few-flowered inflorescences (often only 1 or 2 flowers) with patent, white petals. Yet, several Belgian records of presumed Cotoneaster dammeri turned out to belong with C. xsuecicus, its hybrid with C. conspicuus J.B. Comber ex C. Marquand. The latter usually has at least some branches that are erect or arching (but often rooting at the ends!), smaller leaves, less nutlets per berry and inflorescences with more flowers. The main diagnostic features of both species are opposed in the table beneath.
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C. dammeri |
C. xsuecicus |
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Leaves 15-40 x 7-21 mm. |
Leaves always smaller, 10-23 x 4-10 mm. |
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Usually 5 nutlets per berry (rarely 4). |
2-4 nutlets per berry. |
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Habit strictly procumbent (carpeting), rooting at the nodes (less than 20 cm tall). |
Habit semi-procumbent with at least some branches arching (only rooting at ends), up to 60 cm tall. |
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Literature
Clement E.J. & Foster M.C. (1994) Alien plants of the British Isles. BSBI, London: 590 p.
De Koning J. & van Den Broek (2009) Nederlandse Dendrologie (14th ed.). K.N.N.V.: 547 p.
Dickoré W.B. & Kasperek G. (2010) Species of Cotoneaster (Rosaceae, Maloideae) indigenous to, naturalising or commonly cultivated in Central Europe. Willdenowia 40: 13-45 [available online at: http://user.uni-frankfurt.de/~kasperek/papers/dickore_kasperek_2010.pdf].
Fryer J. & Hylmö B. (2009) Cotoneasters. A comprehensive guide to shrubs for flowers, fruit, and foliage. Timber Press, Portland-London: 344 p.
Grevtsova A.T. (1999) Atlas Cotoneasters. Cotoneaster (Medic.) Bauhin. Kiev, House Orchard, Truck-Garden: 372 p.
Hylmö B. (1993) Oxbär, Cotoneaster i Sverige. Svensk Bot. Tidskr. 87: 305-330.
Karlsson T. (2002) Nyheter i den svenska kärlväxtfloran II. Korsblommiga–flockblommiga. Svensk Botanisk Tidskrift 96: 186-206. [available online at: http://sbf.c.se/www/pdf/96(3-4)/Karlsson.pdf]
Klotz G. (1957) Übersicht über die in Kultur befindlichen Cotoneaster-Arten. Wiss. Z. Univ. Halle, Math.-Nat. 6(6): 945-982.
Lingdi L. & Brach A.R. (2003) Cotoneaster. In: Wu Z.Y. & Raven P.H. (eds.), Flora of China, vol. 9. Science Press, Beijing & Missouri Botanical Garden Press, St. Louis: 85-108 [available online at: http://flora.huh.harvard.edu/china/PDF/PDF09/Cotoneaster.PDF].
Roloff A. & Bärtels A. (2006) Flora der Gehölze (2e Auflage). Ulmer, Stuttgart: 844 p.
Stace C. (2010) New Flora of the British Isles, 3th ed.: XXXII + 1232 p. Cambridge University Press.