White Willow whose scientific name is Salix alba, is a willow species naturally found in Europe, North America and Asia. It has become commonly known as white willow due to the white shade especially visible in the undersides of the leaves. The white willow belongs to the order Malpighiales and family Salicaceae.
Physical features of white willow
The white willow is a deciduous tree that grows up to 10 to 30 meters tall, with a trunk of up to 1 meter in diameter and an irregular crown that usually leans. The bark ranges from gray to brown in color and is characterized by deep fissures in older trees. Typically, the shoots of the White Willow tree appear gray-brown to green-brown. And because its leaves are covered with very fine white silk hairs, specifically on the undersides, the White Willow leaves have a paler appearance compared with those of other willow species. The length of the leaves ranges from 5 to 10 cm with a width of 0.5 to 1.5 cm. In the early part of spring, the White Willow produces flowers in catkins that are pollinated by insects. Being dioecious, an individual White Willow tree can either have male or female catkins. The male catkins range from 4 to 5 cm in length and the female catkins 3 to 3 cm in length at pollination; increasing in length with fruit maturity. In mid summer when fruits mature, the female catkins are composed of numerous small capsules about 4 mm long each harbouring tiny seeds, which help dispersal by wind.
Habitat and ecology
White Willow is distributed in Southern, Northern and Central Europe, North America as well as western and central Asia. This willow tree grows fast, although relatively short-lived, because of its susceptibility to a number of diseases, such as watermark disease characteristically named due to ‘watermark’ staining in the wood, and willow anthracnose. Watermark disease is caused by a bacterium known as Brenneria salicis otherwise called Erwinia salicis; while the fungal anthracnose is caused by the fungus Marssonina salicicola. These plant diseases can be a serious problem on trees cultivated for timber production or ornamental purposes.
The White Willow naturally hybridize with another willow species called crack willow and their hybrid is known as Salix x rubens.
Practical uses of White Willow
In the past, the bark of this willow species was utilized for tanning leather. Its wood is used for timber production because it is tough, strong, and lightweight, though not quite resistant to decay. Charcoal produced from burning wood is a vital component in the manufacture of gunpowder. The stems (withies) obtained from coppiced and pollarded willows are essential materials in crafting, including basket-making.
Medicinal uses
The crystalline form of salicin, the active component of White Willow bark was isolated in 1828 by Henri Leroux, a French pharmacist and Raffaele Piria, an Italian chemist, who eventually succeeded in isolating the acid in its unadulterated state. Salicylic acid, the active ingredient of aspirin, is a chemical derivative of salicin. Salicin has similar effects as salicylic acid, though the former is milder on the stomach lining and has less anticoagulant action than the latter.
The bark of White Willow has also been used as natural remedy for pain, fever and inflammation. It is also commonly used to treat migraine and other forms of headache. Other uses for White Willow bark in herbal medicine include relief of pain due to fibromyalgia, rheumatoid arthritis, Crohn’s disease, surgery and other conditions with pain and inflammation as the characteristic symptoms.
The use of White Willow as natural remedy is beneficial in the sense that it can reduce the use of non-steroidal anti-inflammatory drugs (NSAIDs) which have a few unpleasant effects on the gastrointestinal tract.
White Willow cultivars and hybrids
A few cultivars and hybrids have been used in White Willow horticulture and forest management. These include:
Salix alba ‘Caerulea’
Known as cricket-bat willow, this cultivar is cultivated as specialist timber crop for in Great Britain, largely for cricket bat production as well as other uses requiring tough, lightweight wood that does not easily crack. Its origin is not known, but it’s thought to be a hybrid between White Willow and Crack Willow. It grows very fast with a single straight stem and has longer and wider leaves.
Salix alba ‘Vitellina’
Called the Golden Willow, this cultivar is popularly cultivated in gardens for its shoots, colored golden-brown for 1 to 2 years before becoming brown. This variant is decorative especially in winter. For optimal effect, it is important to coppice it every 2 to 3 years to trigger production of young shoots that are longer with nicer color. Other similar cultivars – chosen for even brighter orange-red shoots – include ‘Britzensis’, ‘Cardinal’, and ‘Cermesina’.
Salix alba ‘Sericea’
The Silver Willow got its name for its very dense white hairs on the leaves, making of the foliage of this White Willow cultivar particularly silvery-white.
Salix alba ‘Vitellina-Tristis’
The Golden Weeping Willow is a weeping cultivar whose yellow branches turn red-orange in winter. Although rarely cultivated now, it remains the number one choice in very cold countries including Canada, Russia, and the northern part of the U.S.
Salix sepulcralis group ‘Chrysocoma’
A hybrid between White Willow and Peking Willow (Salix babylonica), the Golden Hybrid Weeping Willow has largely replaced the Golden weeping Willow.
Growing White Willow trees
White Willow is a fast-growing tree that loves moisture and has spreading root systems that can extend well beyond the perimeter of the canopy. This tree can grow in almost any climate, in USDA hardiness zones 2 through 8 and can withstand winter temperatures as low as -45 degrees Fahrenheit.
You should plant White Willow trees in the fall, at least six weeks prior to the first expected frost. In planting, choose a site with partial to full sunlight, and has soil that’s loose, moist and fertile. Watering should be done deeply once a week during the first year in the fall, spring and summer, thoroughly soaking the soil down to the roots and around them. During the second year and beyond, water your White Willow tree from spring until summer in times of extended dry spells and droughts.
