The genus Salix, as recognised in 2019, is comprised of probably more than 300 distinct species (over 500 if you also accept hybrid species). Many of these species are very similar, sometimes being separated as much by native range as by any other characteristic. Hybridization between species is common, when this is coupled with the high genetic and morphological variability within many species, and different levels of ploidy, the complexity of this genus is clear.
Misidentification of specimens is not rare, even amongst botanists, and many records of plant use will often equally apply to one or more related species that were not seen as distinct when the report was made. Equally, several species not included in the database will be found to have a range of these uses. In general, all species in the genus have medicinal uses, especially as antiinflammatories, analgesics and febrifuges, they can all serve as emergency foods, many of them have flexible stems and can be used in basket making, and many of them can be planted in moist to wet conditions in order to stabilize the soil and improve wildlife habitats.

Common Name: Black Willow

General Information

Salix nigra is a deciduous tree with a broad, open crown and stout branches; it usually grows from 5 - 20 metres tall but ocasionally reaches 40 metres and sometimes is more shrub-like in habit. The trunk is often massive, 200cm or more in diameter, usually leaning and often divided[, , ].
This species is the most commer cially important willow species in North America, where the wood is harvested on a commercial basis. The plant is also harvested from the wild for local use as a food, medicine and source of materials. The tree is used in restoration and soil stabilization projects, it can be used as a pioneer when restoring native woodland and is also grown as an ornamental[].
Salix nigra has a wide distribution so it is assumed that the population is large. At present there are no major threats to the species. The plant is classified as 'Least Concern' in the IUCN Red List of Threatened Species(2013)[].

Known Hazards

None known

Botanical References

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Range

Eastern and southern N. America - Ontario to Quebec, south through central and eastern America to northern Mexico, Texas and Florida.

Habitat

Found in a wide variety of wet soils, growing on floodplains, edges of ponds and lakes, swamps, marshes, white cedar bogs, wet meadows, open fields, roadside ditches, mixed upland deciduous woods along streams; at elevations up to 1,400 metres[].

Properties

Conservation Status	Least Concern
Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Deciduous Tree
Height	12.00 m
Growth Rate	Fast
Pollinators	Bees, Insects
Self-fertile	No
Cultivation Status	Ornamental, Wild

Cultivation Details

Salix nigra is a very cold-hardy plant, able to tolerate temperatures down to around -30°c when fully dormant. The average maximum temperature across its range is 34°c in the summer and 15°c in the winter[] It grows best in climates characterized by an average annual rainfall of 1,300mm, with approximately 40% of that falling in the spring and summer[].
Salix species generally require an open position and abhor dryness at the roots. Whilst many can be found in wet or boggy soils, and prefer a damp, heavy soil, most will grow well in a range of moist but well-drained soils so long as they are fairly deep. Very few are at home in chalky soils[, , ]. This species develops best in fine silt or clay soils in relatively stagnant water, thriving in saturated or poorly drained soil from which other hardwoods are excluded[]. It prefers a pH in the range 4.5 - 7[].
A fast-growing but relatively short-lived species, in its native habitat it can reach 120cm in its first year from seed and 15 metres within 10 years[, ]. Most individuals do not survive past 75 years, after reaching maturity at 55 years and seed bearing age at 10 years[].
Plants are harvested on a commercial basis to supply pulp for papermaking[].
The branches are highly brittle at their base - these can snap off quite easily and when they fall to the ground will often form roots and grow into new plants so long as the soil is moist[, ].
Trees are impatient of root disturbance and should be moved regularly before being planted in their permanent positions, which is best done whilst the plants are young[]. The root system is rather aggressive and can cause problems with drains[]. Plants should not be grown within 10 metres of buildings.
Trees are very susceptible to fire and hot fires can wipe out entire stands[].
Closely related to Salix caroliniana, hybridising with that species where their ranges overlap[]. This species is also likely to hybridize freely with other members of this genus[].
Salix nigra forms natural hybrids with Salix alba, Salix amygdaloides, Salix caroliniana, Salix gooddingii, and Salix lucida[].
The flowers are dioecious, male and female flowers being produced on separate plants. If seed is required then at least one plant of each sex need to be growing in reasonable proximity[].
Salix species are unusual in as much as, although they produce their flowers in catkins, these are insect rather than wind pollinated. Indeed, the flowers of many species are excellent sources of nectar for bees and other insects, especially valuable are those species that flower early in the growing season[].
Plants in this genus are notably susceptible to honey fungus[].

Edible Uses

Inner bark - raw or cooked. It can be dried, ground into a powder and then added to cereal flour for use in making bread etc. A very bitter flavour, it is a famine food that is only used when all else fails[].

Young shoots - raw or cooked. They are not very palatable[].

Medicinal

The bark is anodyne, anti-inflammatory, antiperiodic, antiseptic, astringent, diaphoretic, diuretic, febrifuge, hypnotic, sedative, tonic[, , , , ]. It has been used in the treatment of gonorrhoea, ovarian pains and nocturnal emissions[].
The bark of this species is used interchangeably with Salix alba. It is taken internally in the treatment of rheumatism, arthritis, gout, inflammatory stages of auto-immune diseases, diarrhoea, dysentery, feverish illnesses, neuralgia and headache[].
The bark can be used as a poultice on cuts, wounds, sprains, bruises, swellings etc[].
The bark is removed during the summer and dried for later use[].

The leaves are used internally in the treatment of minor feverish illnesses and colic[].
The leaves can be harvested throughout the growing season and are used fresh or dried[].

The bark, twigs, leaves, leaf buds, and flower buds of all Salix species contain phenolic glycosides, particularly salicin and salicortin (which breaks down when the plant material is damaged to produce salicin). The quantity of these compounds can vary greatly between species, and even within geographical races of the same species. Taste is a simple test to ascertain levels of these compounds - the more bitter the flavour, the more compounds it contains[].
Salicin has several valuable medicinal properties. In particular it is an effective antiinflammatory and pain reliever, and is also a valuable febrifuge[].
Modern medicine has used salicin as a pathway to producing the common pain reliever aspirin and, until a totally synthetic pathway of producing the medicine was discovered, several Salix species were harvested on a commercial basis to obtain salicin.
Many Salix species have a history of traditional use (not always documented). All parts of the plant can be used, but the bark is more commonly employed. Their pain-relieving and antiinflammatory properties make them useful in the treatment of verious conditions including headaches, neuralgia and joint pains, whilst they can also be very helpful in the treatment of fevers[, ].

Agroforestry Uses:

Black Willow is an excellent pioneer forest species in moist soils. It has light seeds that can be blown for long distances in the wind and germinate in open situations. It grows rapidly, quickly establishing suitable conditions for other forest trees to become established and thrive. It is also short-lived and shade-intolerant, so tends to die out after about 50 years and make space for the climax forest trees[, ].
The trees are often used in erosion control projects, their roots forming dense networks that stabilize stream banks and other moist, degraded soils[, ]. Post-size cuttings can be rooted for use in flood projects to prevent gullies from forming[].
A good bee plant, providing an early source of nectar[].

Other Uses

The young stems are very flexible and are used in basket and furniture making[, ]. The twigs can be split in half lengthways, sun-dried and used as the foundation of coiled basketry[]. The plant is usually coppiced annually when grown for basket making, though it is possible to coppice it every two years if thick poles are required as uprights.

A fibre obtained from the stems is used in making paper[]. The stems are harvested in spring or summer, the leaves are removed and the stems steamed until the fibres can be stripped. The fibres are cooked for 2 hours with lye and then beaten with mallets or put through a blender. The paper is red/brown in colour[].

The bark is a good source of tannin[, , ].

A decoction or infusion of the bark can be used as a hair wash to make the hair grow[].
An extract of the bark is used as an ingredient in commercial cosmetic preparations as a skin protector[].

The heartwood is reddish brown, the sapwood nearly white. The wood is very light in weight, usually straight-grained, with a moderately high resistance to shock. It is soft, weak and not very durable, but it does not splinter, warp or check according to some reports[, ], whilst another says that the wood is tough and fairly strong[]. It weighs 27lb per cubic foot[]. Easily worked, it was used extensively at one time for artificial limbs,where strength is not important, and also for purposes such as barn floors, boxes and crates, some items of furniture etc. It is also used to make pulp[, , , , , ].
The wood is used for fuel and can be used to make a good charcoal[, ].

Propagation

Willow seed is very small and light, and has a very short viability, perhaps as little as a few days in some species. It must be surface sown as soon as it is ripe. In nature the seed only germinates in disturbed soils in an open situation. In nursery conditions, sow the seed in a tray in a moderately sunny position and keep the soil moist. Germination is usually quite rapid - prick out the seedlings into individual pots when they are large enough to handle and grow on until large enough to plant out. Plants generally establish better if planted out whilst quite small.
Cuttings of mature wood of the current year's growth or older can root at almost any time of the year, though late autumn is considered best as this produces a better balance of root and stem growth the following spring[]. Plant them in a sheltered outdoor nursery bed or straight into their permanent position and give them a good weed-suppressing mulch. Most species are very easy. Plant into their permanent positions in the following autumn.
Cuttings of half-ripe wood, early to mid summer in a frame. Very easy.