The genus Salix is a diverse group of shrubs and trees encompassing over 400 species worldwide. Many of these are pioneer species, often the first to colonise bare, damp ground following heavy disturbances. Known globally for their incredible growth rates and high concentrations of salicin (the original aspirin), willows are a true marvel of nature.
This post explores how the humble willow bridges the gap between medicine, engineering, and art, and how its story in Scotland is deeply entwined with our beautiful landscapes, history, and a modern resurgence in ecological restoration.
Nativity and species in Scotland
Scotland is home to approximately 14 to 18 native species of willow, depending on botanical classifications of certain hybrids. These species have adapted to survive in every corner and every season of the unpredictable Scottish climate.
Montane - Scotland holds the UK’s only significant populations of rare species like Salix lanata, the Woolly Willow. Under the International Union for Conservation of Nature (IUCN), this species is categorised as ‘vulnerable’ in Great Britain. Its primary threat is overgrazing, exacerbated by reductions in snow-lie. Fortunately, NatureScot and other organisations are implementing deer management and grazing control plans to restore Salix lanatapopulations across the country.
(NatureScot, 2016)
Pioneers - Salix cinerea (Grey Willow) took the #2 spot in a major UK survey for nectar production. Alongside Salix caprea (Goat Willow), these low-land, wet-woodland varieties are vital food resources. Their foliage sustains moths, butterflies, and browsing mammals like deer, rabbits, and beavers (who will fell whole trees just to reach the nutrient-rich fresh growth at the canopy).
(Butterfly Conservation, ND) (Jones, K., 2009) (Memmott, J., ND)
Archaeophytes - ancient introduction now naturalised into the ecosystem. Enter Salix viminalis, or the Osier Willow. This broadleaf tree can reach 7m at maturity, growing up to 1m per season. Brought here hundreds of years ago for basketry, the Osier Willow has a deep connection to local history in Cullen. Keep an eye out for a future post explaining how the Earls of Seafield supported the Cullen fishing fleet with osier holts!
Ancient pharmacology
Historically - as far back as ancient Egyptian and Greek times - people chewed on willow bark to relieve pain and fever. It contains salicin compounds, which the human body converts to salicylic acid after ingestion.
In 1897, Bayer created a more stomach-friendly, synthetic version called acetylsalicylic acid, which we have known as Aspirin since 1899. Fast forward to 1982, and British pharmacologist Sir John Vane was awarded the Nobel Prize in Medicine for discovering exactly how aspirin works - roughly 3,500 years after the first recorded use of willow bark extract as a painkiller!
(Bayer, 2022) (Schwarcz, J., 2022) (Waring, S., 2017)
Disclaimer: Although willow bark is where aspirin originates, please don’t chew your cuttings! Salicin concentrations vary wildly between species and can severely upset your stomach.
The magic "Willow Water" rooting hormone
Willows are incredibly high in indolebutyric acid (IBA) and salicylic acid (SA), making them the perfect ingredient for a DIY rooting hormone. IBA stimulates root formation, while SA helps the plant fight off fungi and bacteria - acting like a proactive antibiotic to strengthen the plant's immune system.
How to make it: Soak chopped willow pieces in water for 48 hours. You can apply this "willow water" as a root drench for crops or use it to water struggling cuttings. If you are rooting your own cuttings in water, save that water and use it on your garden plants. It's the perfect, free by-product.
Managing waterlogged soils
Willows are considered hydrophytic; they have adapted to thrive in waterlogged, saturated, and even anaerobic soils. They are a premier nature-based solution for land management.
Their primary superpower behind the scenes is their high rate of evapotranspiration. A willow acts as a bio-pump, transpiring litres of water per day and effectively lowering the local water table. Beyond water removal, their fibrous root systems stabilize the earth to prevent erosion while creating underground pores that improve aeration and drainage over time. They even act as potent bio-filters, absorbing nitrate and phosphate runoff before it reaches our watercourses.
(Achim, F., 2025) (Farming & Water Scotland, 2025)
Propagation and conservation
For gardeners or landowners in Scotland, the Forestry Commission recommends using seeds or cuttings from local trees that have already adapted to your specific rainfall and soil type.
Willow is incredibly easy to propagate. Here is how to do it:
- Take cuttings during the cold months while the plant is dormant.
- Size matters: Keep cuttings at least 20cm long and about the thickness of your pinky finger.
- Cut correctly: Make the top cut above a bud and the bottom cut below a bud.
- Plant: Root them in water or plant them directly into the ground in February or March. This timing gives the root network a head start before the heat stresses of the unpredictable Scottish summer.
(Reforesting Scotland, 2002)
The 'Infinite Glitch' crop
Hopefully, this post has shown you just how versatile willow is. Highly tolerant of cutting and incredibly easy to propagate, it truly is an ‘infinite glitch’ crop. Taking that first cutting is a step that will benefit you, your garden, and local biodiversity for years to come.
Stay tuned for a future post dedicated to basket weaving and the fascinating local history of osier holts!
Content has been drafted by an actual human and rewritten by AI.