94,129
edits
Changes
From Gardenology.org - Plant Encyclopedia and Gardening Wiki
Jump to navigationJump to searchno edit summary
|image_caption=White Willow foliage; note white undersides of leaves
|image_caption=White Willow foliage; note white undersides of leaves
}}
}}
'''''Salix alba''''' ('''White Willow''') is a species of [[willow]] native to [[Europe]] and western and central [[Asia]].<ref name=rdm>Meikle, R. D. (1984). ''Willows and Poplars of Great Britain and Ireland''. BSBI Handbook No. 4. ISBN 0-901158-07-0.</ref><ref name=rushforth>Rushforth, K. (1999). ''Trees of Britain and Europe''. Collins ISBN 0-00-220013-9.</ref> The name derives from the white tone to the undersides of the leaves.
It is a medium-sized to large [[deciduous]] [[tree]] growing up to 10–30 m tall, with a trunk up to 1 m diameter and an irregular, often leaning crown. The [[bark]] is grey-brown, deeply fissured in older trees. The shoots in the typical species are grey-brown to green-brown. The [[leaf|leaves]] are paler than most other willows, due to a covering of very fine silky white hairs, particularly on the underside; they are 5–10 cm long and 0.5–1.5 cm wide. The [[flower]]s are produced in [[catkin]]s in early spring, and pollinated by [[insect]]s. It is [[plant sexuality|dioecious]], with male and female catkins on separate trees; the male catkins are 4–5 cm long, the female catkins 3–4 cm long at pollination, lengthening as the fruit matures. When mature in mid summer, the female catkins comprise numerous small (4 mm) [[capsule (fruit)|capsules]] each containing numerous minute [[seed]]s embedded in white down which aids wind dispersal.<ref name=rdm/><ref name=rushforth/><ref name=afm>Mitchell, A. F. (1974). ''A Field Guide to the Trees of Britain and Northern Europe''. Collins ISBN 0-00-212035-6</ref>
{{Inc|
{{Inc|
Salix alba, Linn. White Willow. Large tree, with short and thick trunk, not excurrent in habit: branches yellowish brown: lvs. ashy gray and silky throughout, giving a white appearance to the whole tree, 2-4 in. long, elliptical. —Heretofore associated with the next species, from which it differs in color of twigs and vesture and color of lvs., as also in its general habit. It is only occasionally seen in Amer. Var. splendens, Anderss. (S. alba var. argentea, Wimm. S. regalis, Hort.). Lvs. densely silky on both sides, nearly silvery-white while young. The forms of this species not easily distinguishable from one another, can be readily distinguished from many other species. Var. calva, G. F. W. Mey. (S. alba var. caerulea, Smith). Of pyramidal habit: lvs. larger, at maturity glabrescent, more bluish green above and more glaucous below.
Salix alba, Linn. White Willow. Large tree, with short and thick trunk, not excurrent in habit: branches yellowish brown: lvs. ashy gray and silky throughout, giving a white appearance to the whole tree, 2-4 in. long, elliptical. —Heretofore associated with the next species, from which it differs in color of twigs and vesture and color of lvs., as also in its general habit. It is only occasionally seen in Amer. Var. splendens, Anderss. (S. alba var. argentea, Wimm. S. regalis, Hort.). Lvs. densely silky on both sides, nearly silvery-white while young. The forms of this species not easily distinguishable from one another, can be readily distinguished from many other species. Var. calva, G. F. W. Mey. (S. alba var. caerulea, Smith). Of pyramidal habit: lvs. larger, at maturity glabrescent, more bluish green above and more glaucous below.
===Pests and diseases===
===Pests and diseases===
White Willows are fast-growing, but relatively short-lived, being susceptible to several [[disease]]s, including [[Brenneria salicis|watermark disease]] caused by the [[bacterium]] ''[[Brenneria salicis]]'' (named because of the characteristic 'watermark' staining in the [[wood]]; syn. ''Erwinia salicis'') and willow [[anthracnose]], caused by the [[fungus]] ''Marssonina salicicola''. These diseases can be a serious problem on trees grown for timber or ornament.
==Varieties==
A number of [[cultivar]]s and [[hybrid (biology)|hybrid]]s have been selected for [[forestry]] and [[horticulture|horticultural]] use:<ref name=rdm/><ref name=rushforth/>
*''Salix alba'' 'Caerulea' ('''Cricket-bat Willow'''; syn. ''Salix alba'' var. ''caerulea'' (Sm.) Sm.; ''Salix caerulea'' Sm.) is grown as a specialist [[timber]] crop in [[Great Britain|Britain]], mainly for the production of [[cricket bat]]s, and for other uses where a tough, lightweight [[wood]] that does not splinter easily, is required. It is distinguished mainly by its growth form, very fast growing with a single straight stem, and also by its slightly larger leaves (10–11 cm long, 1.5–2 cm wide) with a more blue-green colour. Its origin is unknown; it may be a hybrid between White Willow and Crack Willow, but this is not confirmed.<ref name=rdm/>
*''Salix alba'' 'Vitellina' ('''Golden Willow'''; syn. ''Salix alba'' var. ''vitellina'' (L.) Stokes) is a cultivar grown in gardens for its shoots, which are golden yellow for 1–2 years before turning brown. It is particularly decorative in winter; the best effect is achieved by [[coppicing]] it every 2–3 years to stimulate the production of longer young shoots with better colour. Other similar cultivars include 'Britzensis', 'Cardinal', and 'Chermesina', selected for even brighter orange-red shoots.
*''Salix alba'' 'Sericea' ('''Silver Willow''') is a cultivar where the white hairs on the leaves are particularly dense, giving it more strongly silvery-white foliage.
*''Salix alba'' 'Vitellina-Tristis' ('''Golden Weeping Willow''', synonym 'Tristis') is a weeping cultivar with yellow branches that become reddish-orange in winter. It is now rare in cultivation and has been largely replaced by [[Salix Sepulcralis Group 'Chrysocoma']]. It is however still the best choise in very cold parts of the world like Canada, the Northern U.S.A. and Russia.
*The '''Golden Hybrid Weeping Willow''' ([[Salix Sepulcralis Group 'Chrysocoma']]) is a hybrid between White Willow and Peking Willow ''[[Salix babylonica]]''.
It readily forms natural [[Hybrid (biology)|hybrids]] with Crack Willow ''[[Salix fragilis]]'', the hybrid being named ''[[Salix × rubens]]'' Schrank.<ref name=rdm/>
==Gallery==
==Gallery==
<gallery>
<gallery>
Image:Salix alba 020.jpg|Tree, showing whitish foliage compared to surrounding trees
Image:Illustration_Salix_alba0.jpg|White Willow illustration
Image:Illustration_Salix_alba0.jpg|White Willow illustration
Image:Salix alba(02).jpg|Catkins
Image:Salix alba(02).jpg|Catkins
Image:Salix alba(01).jpg
Image:Salix alba(01).jpg
Image:Salix Alba.jpg|White Willows in winter time
Image:Salix Alba.jpg|White Willows in winter time
File:Salix alba 011.jpg
File:Salix alba bark.jpg
</gallery>
</gallery>
