Holly - Cuileann - (Ilex aquifolium)

The evergreen holly is a native species which forms the shrub layer in some of our oldest woods. You may look for it in woodland, or in the narrow gullies of the Sperrins or Donegal uplands, where holly and rowan can survive the harsh upland conditions.Holly belongs to the genus Ilex and is a member of the Holly family (Aquifoliaceae).

Holly (Ilex aquifolium) is a broadleaved, evergreen tree growing up to 20m and flowering May to August.

Lifespan: 200–300 years.

 

Characteristics

Bark is smooth and thin. Leaves are alternate, dark green, glossy and oval, with wavy margins that terminate in prickly spines. Leaves at the top of the tree are usually spineless. Each leaf can live two to three years.

Holly is dioecious, which means that male and female flowers are found on different individual trees. Flowers have four white petals (approx. 6mm). Male flowers have four stamens and female flowers have a central, green, four-carpel ovary with four styles. Fruits are stalked scarlet berries (7–12mm). Holly is insect pollinated.

Holly is very rarely hermaphrodite with ‘perfect’ flowers where both sexes are represented in one flower. Holly can also reproduce vegetatively from root suckers.

Holly tree
Holly leaves

Distribution

Native in the UK and across Europe, north Africa and western Asia.

Very commonly found in woodland, scrub and hedgerows, especially in oak and beech woodland. Rarer in the far north of Scotland.

Widely planted in parks and gardens and many cultivated forms exist with various foliage and berry colours.

Human value

The wood of holly is white, heavy, hard and fine grained. It is the whitest of all woods; its colour approaching that of ivory and probably the densest of our native hardwoods.

Holly wood stains and polishes well and is used in decorative inlays for furniture or smaller engraving work; it is a popular wood for walking sticks. Holly wood also makes good fire wood and burns with a strong heat.

In some parts of the country holly was actively managed (pollarded) to provide a winter food source for sheep and cattle. Rare stands still exist; the New Forest is one example.

Holly is widely used as a traditional decorative plant in wreaths at Christmas time.

Holly flowers
Holly flowers

Wildlife value

Holly flowers provide a good nectar source for pollinating insects such as bees and bumblebees.

Holly is the food plant for the holly blue butterfly and a number of moth species including the yellow barred brindle, double-striped pug and the holly tortrix.

The berries are popular with the song thrush, mistle thrush, fieldfare and redwing in winter and are also eaten by small mammals such as wood mice and dormice. Holly provides dense protective shelter and good nesting sites for birds such as thrushes, finches, goldcrests, robins and dunnocks.

The deep leaf litter beneath holly provides hibernation sites for hedgehog, toads, slow worms and small mammals.

As one of our few evergreen native trees holly provides a winter food source for deer. The prickly leaves are usually produced lower down the plant as a protection from browsing animals. The leaves of upper branches are usually spineless.

Management

A slow growing, shade tolerant, hardy tree found on well-drained to moist soils from calcareous to acidic at elevations up to 500m above sea level. Tolerant of pollution and providing a good windbreak, holly is an ideal hedging species. It will not tolerate wet or waterlogged soils.

Seeds can be collected in December but are slow to germinate requiring two winters of dormancy (18 months pre-treatment) before they begin to sprout. Holly can also be propagated from semi-hardwood cuttings.

Holly leaf miner may cause damage to foliage and holly leaf blight caused by Phytophthora ilicis may cause dieback. A fungus, Guignardia philoprina, can occasionally infect holly and cause dieback of foliage and shoots.

Holly berries

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Illustrations © Reader’s Digest Association, Inc.
Holly flowers © Jean Robinson
Holly berries © Forestry Commission
All Information provided by Royal Forestry Society

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