What's the difference between Grey and Goat Willow?

The team of instructors and apprentice instructors at Woodland Ways love customers on our courses to ask questions. On the one hand it shows interest and engagement, on the other, it gives us an opportunity to learn. This is one such opportunity when on a forage course I was asked the question "What’s the difference between Goat and Grey Willow?" Which I could not give a 100% definitive answer at the time, so time to hit the books, internet and an arboretum, and write a blog.

The willow family, known scientifically as Salix spp., is a cornerstone of the British landscape, populating riverbanks, wetlands, and open woodlands. This diverse genus includes more than 300 species globally, ranging from minute, prostrate shrubs to impressive, towering trees. While their graceful, often drooping forms and slender leaves are a familiar sight, the accurate identification of individual willow species presents a unique and rewarding challenge for a field botanist, let alone a bushcraft instructor.

The primary difficulty in identifying willows comes from their remarkable propensity for hybridization. Different species readily interbreed, producing offspring with a confusing mix of parental characteristics. This phenomenon is so widespread that it is difficult to determine which willow species were originally native to the UK after the last ice age, as the resulting hybrids have blurred traditional lines of classification. The prevalence of these natural hybrids means that no single identification key can be considered infallible. As a result, the most reliable method for identification is not to rely on a single feature, but to take a holistic approach, observing a suite of characteristics in concert to form a clear and confident conclusion.

Core Principles of Identification
To successfully identify willows, it is essential to move beyond a simple visual inspection and consider the tree's complete profile. This involves understanding its fundamental botanical traits, recognizing how features change with the seasons, and carefully observing multiple parts of the same tree.

1. Growth Habit and Habitat: Willows are predominantly plants of wet soils and damp environments. Most common species are found along riverbanks, streams, lakes, and in wetlands and wet woodlands. An important exception is the Goat Willow (Salix caprea), which, unlike its relatives, is more tolerant of drier conditions and can be found in a wider variety of habitats, including hedgerows and scrubland.
2. The Dioecious Nature: A key characteristic of the Salix genus is that it is dioecious, meaning individual trees are either male or female. The flowers appear as catkins, which are produced in early spring, sometimes even before the leaves emerge. Male and female catkins have distinct appearances: male catkins are often fatter and turn a fluffy yellow as they mature with pollen, while female catkins are typically more slender and green. The timing and appearance of these catkins can be a useful diagnostic clue.
3. Morphological Variability: A crucial aspect of willow identification is recognising that a tree's appearance is not static. Features such as leaf size, shape, colour, and hairiness can change significantly throughout the growing season and may even vary across different parts of a single branch. Environmental factors like moisture, nutrients, and sunlight also influence the tree's phenotype, meaning a species in a shaded, nutrient-rich environment may look different from one in full sun with poorer soil. Therefore, a thorough identification process requires checking multiple leaves and observing the tree's overall form, bark, and twigs to build a composite picture.

This holistic approach to identification could be stated as a mainstay of all plant identification, never relying upon just a single feature, but rather building multiple descriptors and senses of sight, touch, smell, sound, to lead to a 100% positive I.D. and therefore lastly whether taste is an option.

The term "sallow" is often used to describe the smaller, more shrub-like willows, particularly the Goat Willow and the Grey Willow. These species can be confused, but careful observation of their leaves, growth habit, and buds can distinguish them.

Goat Willow (Salix caprea)
The Goat Willow, also known as Pussy Willow, is one of the most recognizable willows, largely due to its fuzzy, silvery-grey catkins that appear in late winter and early spring before the leaves have emerged. These male catkins swell and turn a brilliant yellow as they ripen with pollen. Unlike the long, narrow leaves of most willows, the Goat Willow has broad, oval-shaped leaves with a pointed tip that is often bent to one side. The leaves are hairless on top but covered with a dense, felt-like layer of grey hairs underneath.

A key aspect of this species' identification is its habitat preference. While it can tolerate some wetness, it is more adaptable than many other willows and can be found in drier woodlands, hedgerows, and scrub. It is a pioneer species that often colonizes open ground and, unlike most of its relatives, avoids the continuously saturated soils of wetlands. The Goat Willow typically grows as a small tree or shrub, and its bark develops characteristic diamond-shaped fissures as it matures.

Grey Willow (Salix cinerea)
The Grey Willow is a close relative of the Goat Willow and is often mistaken for it. A key distinguishing feature is its growth habit; the Grey Willow typically grows as a multi-stemmed shrub with no clear trunk, rarely reaching the size of a tree. Its leaves are narrower than those of the Goat Willow and have a crucial identifying feature: the presence of large stipules (tiny leaves) at the base of the main leaf stalks. The twigs and buds are also covered in very short, persistent hairs and are noticeably narrower and smaller than those of the Goat Willow.

The key differentiators for me are:

1. The shape of the leaves – Goat Willow being more rounded and hairy
2. The additional stipules – Grey Willow has the tiny leaves at the base of the leaf stalk
3. Peeled bark – The Grey Willow has ridges on the wood, under the bark

• Goat or Pussy Willow (Salix caprea)
  • Leaves - Broad, oval, twisted tip, felt-like hairs underneath    
  • Twigs - Hairy at first, becoming smooth; yellow/brown buds    
  • Catkins - Appear before leaves; fluffy, silver-grey, turn yellow    
  • Growth Habit - Shrub or small tree (up to 10m)    
  • Primary Habitat - Hedgerows, scrub, drier sites
• Grey Willow (Salix cinerea)
  • Leaves - Narrower than Goat Willow, with large stipules
  • Twigs - Narrower than Goat Willow, persistently hairy
  • Catkins - Shorter and appear later than Goat Willow's
  • Growth Habit - Shrub, multi-stemmed (up to 10m)
  • Primary Habitat - Damp, but not continuously saturated, sites

Willow is an exceptionally versatile resource in bushcraft, with a wide range of uses derived from its wood, bark, and pliable branches. While the general uses are consistent across many species, there can be subtle differences in properties, and some species may be preferred for specific tasks.

General Bushcraft Uses for Willow

• Cordage and Rope: The inner bark of willow is an excellent material for making cordage. The bark can be peeled from young, straight shoots and then processed by scraping off the outer bark, boiling the inner bark strips, and twisting them into strong, durable rope.
• Basketry and Weaving: The flexible, strong, and pliable nature of willow rods makes them a traditional and preferred material for basket weaving, as well as for making other woven items like fish traps, furniture, and living fences (wattle fences). The ability to soak and re-malleable the rods after drying makes it a very forgiving material to work with.
• Medicinal Uses: Willow bark contains salicin, a compound with pain-relieving and anti-inflammatory properties. This is a natural precursor to aspirin. In a bushcraft context, the bark can be chewed or made into a tea to alleviate pain, reduce fever, and treat other ailments. It's important to note that this should be used with caution, and its use is not a substitute for modern medical care.
• Fire-making: The wood of willow can be used as a friction wood for fire-starting methods like the hearth of a bow drill set.
• Containers and Tools: The lightweight and workable wood can be used to carve various tools and objects. The branches are also suitable for making things like fishing poles, while the wood's resistance to splintering has historically made it useful for things like artificial limbs (and cricket bats).
• Tinder: The fluffy catkins of the willow can be used as a natural tinder to catch a spark or ember.
• Charcoal: Willow wood can be easily made into high-quality charcoal, which is useful for drawing or for creating a fine powder that can be mixed with water to treat indigestion.

Are the Uses the Same Across All Species?
While the core uses of willow (cordage, weaving, medicine, etc.) are generally applicable to most species, there are variations that can make some species more suitable for a particular task.

• Flexibility and Weaving: Different willow species have varying degrees of flexibility and strength. Some species might have very straight, flexible shoots ideal for basketry, while others might be more brittle. For example, some artisans prefer specific cultivated varieties for their weaving projects.
• Medicinal Strength: While all willow bark contains salicin, the concentration can vary between species and even depending on the growing conditions. Some herbalists have their favourite species, like white willow (Salix alba) or black willow (Salix nigra), which are well-known for their medicinal properties.
• Wood Properties: The physical properties of the wood can differ. While many willows are suitable for fire-making, certain species might be preferred for their specific density and friction-creating characteristics.

The fundamental bushcraft applications of willow are consistent across the genus. Therefore, an argument could be made, as long as you are 100% certain it is a willow, knowing the exact species, or the fact it may be a hybrid, is not going to deter you from using it as a bushcraft resource.