The Willow family or Salicaceae and their uses. Part 1: The Willows or Salix spp.

The Salicaceae or Willow family is now a much larger family.

It just used to include the willows, poplar, aspen, and cottonwoods.

Pollarded Willows (Salix alba) in a very Dutch Landscape (MS)

Genetic studies summarized by the Angiosperm Phylogeny Group (APG) have greatly expanded the circumscription of the family to contain 56 genera and about 1220 species, including the Scyphostegiaceae and many of the former Flacourtiaceae.

BUT; fortunately for us, in the British Isles it  has only two main genera, namely the Poplar and the Willow. Although the flowers (as always in traditional classification) determine the ultimate genus and whether it is a Willow or Poplar, most of us can easily tell the difference from the leaves. All the Poplars have a triangular, broad oval, to heart-shape outline with often a long leaf stem (petiole) whilst most of the Willows have long, narrow leaves or roundish, much smaller leaves than Poplars.

When there are no leaves in winter the tree could be identified by the winter buds, where Willows just have one outer scale and the Poplar has several. However as there is much to say about the Willow, I will leave the Poplar for another blog in the future!

Pictures by Matt Summers (MS) and Mike Poulton unless stated. The links provided on the scientific and common plant names provide more detailed information as well as good pictures on each species. Also special thanks to PFAF which provides a wonderful plant database of not just native plants but any useful plants all over the world.

This time I will include all the records of the entries of the ‘Online Atlas of the British and Irish Flora’ (BRC) or National Biodiversity Network link (NBN) next to the scientific and common names.

First a bit about the classification of the Willows.

“ Identification is often made difficult by the extensive degree of hybridisation” (68 combinations at present known in B.I., of which 20 are hybrids between 3 species). Only those hybrids considered certainly or very probably correctly identified are listed in Stace.

Hybrids can also be formed due to us planting Willows as an ornamental or for basketry in vicinity of other native Willows.

Catkins and both young and mature leaves (collected in July- September) are desirable for correct identification.

The genus Salix or Willow is separated in 3 sections. As always in classification the species in each section have things in common.

The first Section is SALIX and has 10 species of which 5 can be said to be true natives and 2 are archaeophytes. They are all trees or tall shrubs.

These are:

Section 2 is VETRIX and has shrubs or small trees.

Section 3 is CHAMAETIA, which are all Dwarf shrubs and has only got 3 (native) species.

Much of the below information comes from Wikipedia. But for easy reading I will edit the information into bullet points as far as possible.

General information:

Willows, also called Sallows, and Osiers, form the genus Salix which are  around 400 species of deciduous trees and shrubs, found primarily on moist soils in cold and temperate regions of the Northern Hemisphere. Most species are known as Willow, but some narrow-leaved shrub species are called Osier, and some broader-leaved species are referred to as Sallow (from Old English sealh, related to the Latin word salix, willow). Some willows (particularly arctic and alpine species) are low-growing or creeping shrubs; for example, the Dwarf Willow (Salix herbacea) rarely exceeds 6 cm (2.4 in) in height, though it spreads widely across the ground.

Ornamental Use:

Several native willows are attractive enough to plant in the garden or for the rockery if it is a Dwarf Willow!

Salix caprea ‘Kilmarnock’ or Kilmarnock Weeping Willow

This is a stiffly pendulous small tree with yellowish branches, ovate leaves, and large grey catkins with yellow anthers opening before the leaves. You can watch this Youtube film in order how to prune it after flowering.

An attractive large Weeping Willow (Picture by Mike Poulton)

Salix babylonica or Weeping Willow is a commonly planted tree in large parks or gardens and especially looking good in early spring near water with its large lime-green foliage nearly touching the water. It is however not native.

There are several other ornamental willows, usually not native species such as :

Salix matsudana ‘Tortuosa’ or Corkscrew Willow

Salix udensis ‘Sekka’ or Japanese Fantail Willow

An article especially about Weeping Willows and other ornamental willows can be found here.

Medicinal Uses:

  • The leaves and bark of the Willow tree have been mentioned in ancient texts from Assyria, Sumer and Egypt as a remedy for aches and fever, and in Ancient Greece the physician Hippocrates wrote about its medicinal properties in the fifth century BC!
  • Native Americans across the Americas relied on it as a staple of their medical treatments. It provides temporary pain relief.
  • Salicinis metabolized into salicylic acid in the human body, and is a precursor of aspirin.

Agricultural Uses:

  •  Willows produce a modest amount of nectar from which bees can make honey, and are especially valued as a source of early pollen for bees.
  •  Poor people at one time often ate willow catkins that had been cooked to form a mash.

Manufacturing and historical uses:

 Some of  the human race’s  earliest manufactured items have been made from Willow.

  • A fishing net made from Willow dates back to 8300 BC. Basic crafts, such as baskets, fish traps, wattle fences and wattle and daub house walls, were often woven from Osiers or Withies (rod-like Willow shoots, often grown in coppices).
  • One of the forms of Welsh coracle boat traditionally uses Willow in the framework.
  • Thin or split Willow rods can be woven into wicker, which also has a long history. The relatively pliable Willow is less likely to split whilst being woven than many other woods, and can be bent around sharp corners in basketry.
  • Willow wood is also used in the manufacture of boxes, brooms, cricket batscradle boards, chairs and other furniture, dolls, flutes, poles, sweat lodges, toys, tool handles, veneerwands and whistles.
  • In addition, tannin, fibre, paper, rope and string can be produced from the wood.
  • Willow is also used in the manufacture of double basses for backs, sides and linings, and in making splines and blocks for bass repair.

Wildlife Use:

Arts and Crafts Use:

  • The thinner stemmed willows are used for weaving baskets
  • Willow is used to make charcoal (for drawing)
  • Living sculptures are created from live Willow rods planted in the ground and woven into shapes such as domes and tunnels.  
  • Willow stems are also used to create garden features, such as decorative panels, obelisks and garden constructions such as bowers.

                                                                                                                   

 Almost all Willows take root very readily from cuttings or where broken branches lie on the ground. The few exceptions include the Goat Willow  (Salix caprea) and Peachleaf Willow (Salix amygdaloides).  

 One famous example of such growth from cuttings involves the poet Alexander Pope, who begged a twig from a parcel tied with twigs sent from Spain to Lady Suffolk. This twig was planted and thrived and legend has it that all of England’s Weeping Willows are descended from this first one.

Energy Use:

Willow is grown for biomass or biofuel, in energy forestry systems, as a consequence of its high energy in/energy out ratio, large carbon mitigation potential and fast growth. Large-scale projects to support Willow as an energy crop are already at commercial scale in Sweden. Programs in other countries are being developed through initiatives such as the Willow Biomass Project in the US, and the Energy Coppice Project in the UK.  

Environmental Use:

Willows are often planted on the borders of streams, so their interlacing roots may protect the bank against the action of the water. Frequently the roots are much larger than the stem which grows from them.

Use in Religion:

 Willow is one of the “Four Species” used ritually during the Jewish holiday of Sukkot. In Buddhism, a Willow branch is one of the chief attributes of Kwan Yin, the bodhisattva of compassion. Christian churches in northwestern Europe and Ukraine and Bulgaria often used Willow branches in place of palms in the ceremonies on Palm Sunday.

Pollarding:  A pruning system involving the removal of the upper branches of a tree, promotes a dense head of foliage and branches. In ancient Rome, Propertius mentioned pollarding during the 1st century BC. The practice has occurred commonly in Europe since medieval times and takes place today in urban areas worldwide, primarily to maintain trees at a predetermined height.

The frosted ‘bottle brushes’ of typical pollarded willows in Ter Aar, Netherlands (MS)

In my native lowland Holland, willows are often seen neatly pollarded along roads, ditches and rivers. Usually Salix alba is used for this. This is traditional and aesthetical as well as practical when the water table is mostly very high and in combination with strong winds, tall trees would just keel over!

Salix alba  var. vitellina as seen at Wightwick Manor (National Trust) (Picture by Matt Summers)

The form Salix alba  var. vitellina ‘Britzensis’ can also be seen with its glowing orange red stems in winter.

Traditionally, people pollarded trees for one of two reasons:

For fodder to feed livestock or for wood.

  • Fodder pollards produced “pollard hay”, which was used as livestock feed; they were pruned at intervals of two to six years so their leafy material would be most abundant.
  • Wood pollards were pruned at longer intervals of eight to fifteen years, a pruning cycle that tended to produce upright poles favoured for fence rails and posts, as well as for boat construction.

One positive consequence of pollarding is that pollarded trees tend to live longer than unpollarded specimens because they are maintained in a partially juvenile state and because they do not have the weight and windage of the top part of the tree.

 Older pollards often become hollow, so can be difficult to age accurately. However an interesting garden can grow inside those old crowns!

Pollards tend to grow slowly, with narrower growth rings in the years immediately after cutting.

Unusual non native willow in Sutton Park:

Salix eriocephala  or Missouri River willow or Heart-leaved Willow, was recently found in Sutton Park as a non native species.

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