Arctic willow  (Salix arctica)

The Arctic willow has yet to be is classified by the IUCN.

The Arctic willow (Salix arctica) is a low-growing shrub, which grows flat along the ground and usually forms dense matted structures (3) (4). The Arctic willow is highly variable in its appearance and size, with leaf shape and growth known to differ extensively throughout its range (4).

The leaves of the Arctic willow are more or less oval-shaped (3), and have a smooth margin and a pointed tip (4) (5). They are green and glossy on the upperside and pale grey-green on the underside (3) (4) (5). The Arctic willow produces long, cylindrical, dense clusters of flowers, known as ‘catkins’, which contain either the male or female flower (2). These flowers have a brown or black bract at the base, which has straight hairs on the underside (2). The female catkins are hairy and are usually between one and eight centimetres in length (3) (5). The male catkins are smaller, only growing up to four centimetres in length (3). The catkins of both sexes grow from the sides of the stems, occasionally appearing to grow from the tip (3) (5).

The stems of the Arctic willow are glossy and free from hair and can vary in colouration between yellow-brown, grey-brown or red-brown (2). Young branches are also highly variable in colouration and can be yellow-brown, red-brown or violet (2), becoming browner over time (5). Young growth has a dense cover of white hair, which is gradually lost as the plant matures (5).

Some scientists recognise a number of subspecies of Arctic willow, although they are not universally accepted (3).

A species with a widespread distribution, the Arctic willow occurs throughout northern Canada, Alaska, Greenland, China, Far East Russia and Iceland. The northern United States and northern Europe are the most southerly points of this species’ range (2) (4).

The Arctic willow is found in Arctic and alpine tundra and mountainous regions (4), where it grows in both acidic and calcareous soils (3) (6). The habitat of this adaptable plant varies greatly, including both dry and wet areas, which can be protected or exposed, and both acidic and alkaline soils (4). It is also found in meadows, fens, Sphagnum bogs and around the edges of pools and snowfields (2) (5). Throughout its range, the Arctic willow can be found up to elevations of 2,000 metres (2).

The Arctic willow can often be found living alongside other plant species such as the snow willow (Salix reticulata) (3).

The Arctic willow is dioecious, with the male and female flowers located on separate plants (3). Flowering take place in June and July, with the fruits ripening in August (4). After dispersal, the seeds of the Arctic willow are dormant for 30 days until germination occurs (3).

As well as by seed dispersal, reproduction in the Arctic willow also takes place through vegetative root growth at various points along the stem (5). As a deciduous plant, the Arctic willow sheds its leaves at the end of the growing season (3).

The catkins of the Arctic willow may be much warmer than the surrounding air temperature. On calm, sunny days, female catkins may be up to 8.5 degrees Celsius warmer than the temperature of their surroundings and this difference in temperature speeds up pollen and seed growth, as well as attracting insects (3).

The Arctic willow has a symbiotic relationship with mycorrhizal fungi, which enables the Arctic willow to take up nutrients into the root more efficiently (3).

The Arctic willow is eaten throughout its range by many different animals including muskox (Ovibos moschatus), Arctic hare (Lepus arcticus), ptarmigan (Lagopus muta) and reindeer (Rangifer tarandus), with the younger buds and leaves being particularly popular (2) (3) (7). 

The leaves and bark of many willows are used by local people for medicine, while the fibres from the twigs and bark are used for making baskets and clothing (3). The Arctic willow is also used for fuel in some areas (3). This common and widespread species is not currently thought to be threatened.

There are not known to be any specific conservation measures currently in place for the Arctic willow.

Find out more about plant conservation around the world:

• Plantlife International:
  http://www.plantlife.org.uk/international

Find out more about the Arctic willow:

• Flora of North America - Arctic willow:
  http://efloras.org/florataxon.aspx?flora_id=1&taxon_id=200005753
• Francis, J.K. (204) Salix arctica. In: Wildland Shrubs of the United States and its Territories: Thamnic Descriptions:Volume 1. General Technical Report IITF-WB-1, U.S. Department of Agricultur, Forest Service, International Institute of Tropical Forestry, San Juan, Puerto Rico and Rocky Mountain Research Station, Fort Collins, Colorado. Available at:
  http://www.fs.fed.us/global/iitf/pdf/shrubs/Salix%20arctica.pdf