James Common

Willow-leaved Cotoneaster

Background

Cotoneaster salicifolius forms a few-stemmed, tree-like shrub to a maximum of 6-8 metres. Named for its willow-like leaves, it is native to South and central China where it inhabits mountainous areas and mixed forests but has been widely introduced across the globe as an ornamental plant on account of its attractive foliage and fruits. The type specimen was collected in 1869 by A. David and first published in 1888.

The status of Cotoneaster salicifolius in cultivation remains somewhat unclear. Some sources state that the species is popular in cultivation (1) while others claim that true C. salicifolius is in fact rare in horticulture and perhaps confused with the very similar Cotoneaster flocossus (2). However, Fryer and Hylmo (2009) suggest that the name C. flocossus is often erroneously applied to specimens of C. salicifolius, meaning that the plants grown in gardens and as components of amenity planting schemes are indeed the true species (3).

Cotoneaster salicifolius is widely naturalised outside of its native range, largely as a bird-sown alien. This includes much of Western and central Europe, parts of Scandinavia and areas of North America. In Britain, it is one of our more widespread naturalised cotoneasters.

Cotoneaster salicifolius Habitat

In my experience of C. salicifolius, it is almost always found in dry, stony and sunny habitats, usually atop calcareous substrates. Typically, this includes walls, pavement cracks, post-industrial areas, rail sidings and riverside masonry. It is also known from woodland, scrub, dunes and hedgerows.

Identifying Cotoneaster salicifolius

Cotoneaster salicifolius and indeed, other cotoneasters within the Salicifolii Series differ from other species in having elongate, lanceolate leaves with veins which are often deeply impressed. In some cases, the leaf undersides are also hairy. They tend to form mid-sized shrubs to small trees and typically, possess erect branches with branchlets that are mostly villous-strigose. Glabrous petals and nutlets ranging in number from 2-4 are also a good indicator (3).

C. salicifolius itself typically forms a large shrub or small tree. It sports evergreen, coriaceous leaves which are distinctly lanceolate, and measure 4o-90 x 13-23mm. The upper leaf surface is noticeably rugose, dark green and shiny, and initially at least, tends to be sparsely pilose. The number of veins (covered below) may also be useful. The lower leaf surface tends to be greyish-green and densely villous at first; though these hairs wear off in time.

This species sports large and attractive flower clusters, sporting 10-50 individual flowers. Individual flowers measure 5-6mm and possess white, glabrous petals. The fruits of C. salicifolius are globose, measure 5-7mm and are bright red and sparsely pilose. Inside, the number of nutlets is typically 2 but may number 4-5 on occasion. For more detailed notes, please see Fryer & Hylmö (2009).

Similar species

While C. salicifolius is distinguished from most other naturalised cotoneasters on account of its lanceolate, willow-like leaves, it does resemble several other closely related species. The shiny upper-leaf surface is a good separating factor here but to be sure, other features should be examined. Included below are comparisons between this species and several others known to occur in the UK.

Willow-leaved Cotoneaser may also closely resemble the cultivated hybrid, Cotoneaster x watereri. A cross between C. salicifolius and the Tree Cotoneaster (Cotoneaster frigidus), this one readily escapes and is equally as likely to turn up in a naturalised state. A handy comparison of the two can be found here thus there is little point duplicating this here but it may be useful to note that C x watereri is the one more likely to be found in shade.

	C. salicifolius	C. flocossus	C. hylmoei	C. henryanus
Fruit	5-7mm, bright red, sparsely pilose, calyx lobes flat, nutlets 2 (rarely 4-5)	5-7mm, bright red, sparsely villous, calyx lobes depressed, nutlets 3 (rarely 4)	5mm, red, sparsely pilose, calyx lobes depressed and villous, nutlets 2-3	5-6mm, rich red, villose-strigose, calyx lobes depressed, nutlets 2 (rarely 2-3)
Flowers	5-6mm, white, glabrous; filaments white, anthers purple.	5-6mm, white, glabrous; filaments white anthers purple	7-9mm, pale pink, glabrous; filaments white/pink, anthers reddish black	6-7mm, white, glabrous; filaments white, anthers purple
Leaf size	40-90mm x 13-23mm	60-77mm x13-19mm	45-70mm x 18-30mm	70-114mm x 22-44mm
Leaf above	Rugose, dark green, shiny, initially sparsely pilose, margin recurved, veins 7-12	Slightly rugose, dark green, dull, initially sparsely brownish pilose, veins 7-10	Rugose, dark green, shiny, glabrous, margin slightly recurved, veins 9-14	Slightly rugose, dark green, dull, initially sparsely brownish pillose, veins 7-10
Leaf below	Gray-green, initially densely villous	White tomentose-floccose. Becoming subglabrous and glaucous	silvery-white tomentose	Densely brownish villous-strigose
UK Status	1301 records; widespread	1 record; Central Scotland	11 records, widely distributed	24 records; scant but widespread

Status in the UK

C. salicifolius is one of the more widespread naturalised cotoneasters in the UK; particularly so in England where it can be found nationwide with noticeable clusters around urban centres. It is scarcer in Scotland but again, is plentiful in urban areas of the central belt. It was first recorded in the wild in 1966 from North Hampshire (4). For more information, see here.

References

1. Dickoré, W.B. & Kasperek, G. (2010). Species of Cotoneaster (Rosaceae, Maloideae) indigenous to, naturalising or commonly cultivated in Central Europe. Willdenowia 40: 13-45
2. Verloove, Filip. (2014). Het genus Cotoneaster in België. Dumortiera. 103. 3-29.
3. Fryer, J.; Hylmö, B. (2009). Cotoneasters: a comprehensive guide to shrubs for flowers, fruit, and foliage. Timber Press, Portland.
4. Cotoneaster salicifolius Franch. in BSBI Online Plant Atlas 2020, eds P.A. Stroh, T. A. Humphrey, R.J. Burkmar, O.L. Pescott, D.B. Roy, & K.J. Walker. https://plantatlas2020.org/atlas/2cd4p9h.pw4 [Accessed 29/10/2023]