Common names: Holly 

Irish name: Cuileann 

Latin name: Ilex aquifolium 

Family: Aquifoliaceae 

Origin: Native 

Tree type: Evergreen broadleaf tree

How it looks

Shape, bark, twigs 

Holly trees can grow to 15m tall. Their bark is smooth and thin with lots of small, brown 'warts'. With age, it will develop some long, narrow cracks.  

Leaves 

Holly leaves are evergreen, retaining their green colour throughout the year. Individual leaves remain on the tree for 2 to 3 years. They are glossy dark green on their upper surface and have a paler green hue on the underside. These leaves are leathery and oval, measuring 5 to 12 cm in length and 2 to 6 cm in width.

As a protective feature, smaller trees and lower branches of older trees have leaves with three to seven sharp spines along their margins, some pointing upward and others downward. Higher up on the tree, where leaves are out of reach of herbivores, the leaves typically have fewer or no spines.  

Flowers 

Holly trees do not produce flowers until they reach approximately 20 years of age. They exhibit dioecious characteristics, meaning they have separate male and female trees. Male flowers feature stamens covered in pollen and smaller, sterile stigma, while female flowers have larger stigma and smaller, sterile stamens without pollen. Both male and female flowers are small and creamy white, with four petals measuring 6 to 10 mm. They bloom in clusters near the base of the leaves from May to July. 

Fruits 

After insect pollination, female flowers develop into berries measuring 6 to 10 mm in diameter. It's important to note that only female holly trees produce berries since holly trees are either male or female (dioecious). The berries initially appear green but ripen to a vibrant red by mid-winter. Each berry contains four seeds, and birds that consume the fruit disperse these seeds through their droppings. 

Similar species 

Holly is hard to confuse with other trees. However, many cultivated varieties exist in gardens and parks.

Where to find it

Holly has adapted to thrive in shaded environments, making it well-suited for the dimly lit understory of our native broadleaf woodlands. It can flourish in various soil types, except for excessively damp conditions, tolerating areas where many other trees and shrubs struggle, such as the challenging environments of the Sperrins or Donegal uplands. Holly is a common sight throughout Ireland, often found in woodlands, scrublands, and hedgerows. 

Holly is native to Western, Central, and Southern Europe, North Africa, and Western Asia. It has also been introduced to other regions, including New Zealand, temperate parts of Australia, and the Pacific Northwest of North America, where it has posed challenges as an invasive species.

Cultural importance

History | Myth | Literature

History 

Charcoal found during the archaeological excavation of an Neolithic occupation site in Tullahedy, Co. Tipperary indicates that holly was being used in Ireland for firewood as early as c. 3700-3400 BC. It has been suggested that the wood burnt at this site was used for either manufacturing or ritual purposes. Similarly, charcoal samples from Bronze-Age (c. 2200-800 BC) Burnt Mounds, otherwise known as Fulachtaí Fiadh or early cooking pits, discovered in Co. Meath were found to contain holly. Evidence from excavations at Edercloon, Co. Longford demonstrate that holly was also used in the construction of Bronze and Iron Age (800-400 BC) trackways for traversing and accessing the bog.  

In early Medieval Ireland (c. 400-1100 AD), holly, despite being a small tree, was considered one of the ‘Nobles of the Wood’. This is likely due to its versatility, being used for animal fodder, the manufacture of chariot shafts, cooking spits, spear shafts and possibly the construction of deer traps. Along with hazel and ash, holly was especially cultivated to produce these items. Adding to this significance, holly was used to represent the character for the letter ‘T’ in the early Irish Ogham alphabet:

An analysis of decorated wood from archaeological excavations of Viking-age material in Dublin indicates that on rare occasion, objects were also crafted from holly during this period. 

Charcoal found in Medieval pits dating to the fourteenth and fifteenth centuries AD reveals that holly was being used for firewood during this period as well. 

The Irish name for holly, Cuileann, is commonly found in Irish placenames throughout the country. Examples include, Gleann Chuilinn or Glencullen in Co. Dublin, which translates as ‘valley of the holly’, and Oileán an Chuilinn or Garinish Island in Co. Cork, which means ‘island of the holly’.

Myth, Legend and Folklore 

Holly is traditionally associated with protection, magic, strength and purification.  

The name of the holly derives from the word ‘holy’ due to the belief that its red berries were reflective of Christ’s blood. Hence, its connection to Christmas. In Ireland, the holly is especially connected with the Saint Stephen’s Day (December 26th) ‘wren boy’ tradition, where boys hunt a wren, then decorate it with holly and ribbons, and go from house to house begging for a penny. It was also believed that if one was whipped with holly, they would be purified through the blood drawn as a result of this process. Furthermore, the presence of holly as a decoration in one’s home at Christmas, was thought to be protective. However, in some cases, when used in the wrong way, it could have a negative influence. For instance, holly was connected with the fairies and it was believed that any misuse of it would anger them. If it was planted near the house, it was believed that the daughter of that house would not conceive. Likewise, if it was used to drive a cow, it was thought that it would bestow illness on the cow. 

The protective power of the holly recurs in myth and legend, especially in stories of saints, including the tale in which Saint Ronan is protected by a ring of holly from an attacker. The holly is also symbolic of warriors and features frequently in stories about the heroes Fionn Mac Cumhaill and Cúchulainn, either being used by them in the form of arrows, darts, chariot poles and other weapons to attack an enemy or vice versa. In the same vein, the Irish myths also link holly with the pagan god, Lugh who was associated with light, war, kingship and the arts. As such, holly is also connected with the summer festival of Lughnasa on August 1st, when chariot races are reputed to have been held.

Literature 

In the medieval Irish poem, Sweeney’s Lay, the protective qualities of the holly are referenced: ‘Oh, Holly, little sheltering one, Thou door against the wind’. In his poem, The Vision, Robert Burns describes the Scottish muse as having ‘Green, slender, leaf-clad holly-boughs Were twisted, graceful, round her brows’. The holly also features significantly in a positive capacity in William Shakespeare’s poem, Blow Blow Thou Winter Wind. 

Value to wildlife

Holly stands out as a valuable resource for wildlife due to its enduring, spiky, and densely packed foliage, providing year-round shelter for birds and animals. The fallen leaves, which take years to decompose, offer an abundant supply of protective nesting material for small mammals. During the spring, holly's protective canopy becomes a preferred choice for birds seeking refuge while constructing their nests. 

Holly's blossoms serve as a source of nectar and pollen for bees and other pollinators. The holly blue butterfly relies on holly as a primary food source for its caterpillars. In the spring, these tiny blue butterflies lay their eggs on holly's flowers, serving as sustenance for the emerging caterpillars, along with the berries and terminal leaves. Various moth species, including the yellow-barred brindle, double-striped pug, and holly tortrix, also consume holly leaves. Additionally, holly leaves provide food for the larvae of the holly leaf miner fly, which create distinctive trails or "mines" within the leaves. 

The clusters of vibrant red holly berries are a significant winter food source for various animals. The mistle thrush is renowned for its vigilant protection of these berries from other birds. Holly, one of the few evergreen broadleaved trees in Ireland, is a crucial food source during the winter months. Surprisingly, despite its spiky and leathery leaves, it is an important winter food source for mammals such as our native red deer.

Threats

The holly leaf miner fly may cause damage to foliage, and holly leaf blight may cause dieback. However, there are no significant pests or diseases that threaten holly. 

To learn more about threats to Irish trees, visit ‘Threats to Trees.’

Uses

Holly is an excellent choice for hedges, as it can tolerate grazing livestock. These animals typically only consume the youngest and most tender leaves and shoots. 

The holly tree yields a highly durable, dense, fine-grained white wood frequently used in carving and inlay work. It has even been stained black to serve as a substitute for ebony in piano manufacturing. Holly wood is also used in crafting white chess pieces, mathematical instruments, knife handles, and walking sticks. 

In Western traditions, holly is a popular decoration during the Christmas season. Additionally, holly wood is a valuable source of firewood, burning with intense heat.

References

Kelly, F. 1999. Trees in Early Ireland, Augustine Henry Memorial Lecture 11th March 1999, Irish forestry: Journal of the Society of Irish Foresters, 56, pp. 39-57. 

MacCoitir, N. 2015. Ireland’s Trees: Myths, Legends and Folklore. Cork: The Collins Press. 

McLoughlin, J. 2016. Trees and woodland names in Irish placenames, Irish Forestry, 73, 239-257. 

McMahon, P. 2023. Island of Woods: How Ireland Lost Its Forests and How to Get Them Back, Dublin: New Island Books. 

McManus, D. 1991. A Guide to Ogam, Maynooth: An Sagart.  

Moore, Catriona. 2021. Between the Meadows: The archaeology of Edercloon on the N4 Dromod–Roosky Bypass: 11 (TII Heritage), Dublin: Transport Infrastructure Ireland. 

Neeson, E. 1991. A History of Irish Forestry, Dublin: The Lilliput Press Ltd. 

O'Carroll, E. 2010. Ancient Woodland Use in the Midlands: Understanding Environmental and Landscape Change through Archaeological and Palaeoecological Techniques, In: Creative minds, Production, Manufacture and Invention in Ancient Ireland. NRA Monograph Series issue 3. 

O’Carroll, E. 2011.Wood Remains, in R.M. Cleary and H. Kelleher (eds.), Archaeological Excavations at Tullahedy, County Tipperary. Cork: The Collins Press 

Poetry Soup. 2023. The Vision by Robert Burns. Poetry Soup. Online: 91. The Vision - A Poem by Robert Burns (poetrysoup.com)  

Raftery, B. 1996. Trackway Excavations in the Mountdillon Bogs, Co. Longford, Irish Archaeological Wetland Unit Transactions: Volume 3, Dublin: Crannóg Publishing. 

Stroh, P. A., Humphrey, T. A., Burkmar, R. J., Pescott, O. L., Roy, D. B., & Walker, K. J. 2023. BSBI Online Plant Atlas 2020. https://plantatlas2020.org/atlas

Tree Council of Ireland. 2024. Native Irish Trees. Tree Council of Ireland. https://www.treecouncil.ie/native-irish-trees 

Wallace, P. F. 2016. Viking Dublin: The Wood Quay Excavations. Sallins: Irish Academic Press. 

Woodland Trust. 2024. A-Z of British trees. Woodland Trust. https://www.woodlandtrust.org.uk/trees-woods-and-wildlife/british-trees/a-z-of-british-trees/