Ilex, or the holly genus, is a genus of 400 to 600 species of flowering plants in the family Aquifoliaceae, and the only living genus in that family. The species are evergreen and deciduous trees, shrubs, and climbers from tropics to temperate zones worldwide. In Europe the genus is represented by a single species, the classically named holly, Ilex aquifolium.

Common name: ‘Holly’  or ‘Common Holly’- the name “holly” in common speech refers to Ilex aquifolium, specifically stems with berries used in Christmas decoration. By extension, “holly” is also applied to the whole genus. The origin of the word “holly” is considered a reduced form of Old English hole(ġ)n, Middle English Holin, later Hollen.

Native areas: Ilex aquifolium is native to western and southern Europe, northwest Africa, and southwest Asia.

Historical notes: Ilex in Latin means the holm-oak or evergreen oak (Quercus ilex). Despite the Linnaean classification of Ilex as holly, as late as the 19th century in Britain, the term Ilex was still being applied to the oak as well as the holly – possibly due to the superficial similarity of the leaves.

Ilex aquifolium

Features: Holly is an evergreen, conical tree growing to 5-10 metres tall. The leaves are 5–12 cm long and 2–6 cm broad; they are evergreen, lasting about five years, and are dark green on the upper surface and lighter on the underside, oval, leathery, shiny, and about 5 to 9 cm long. In the young and in the lower limbs of mature trees, the leaves have three to five sharp spines on each side, pointing alternately upward and downward, while leaves of the upper branches in mature trees lack spines.

The flowers are white, four-lobed, and pollinated by bees. Holly is dioecious, meaning that there are male plants and female plants. The sex cannot be determined until the plants begin flowering, usually between 4 and 12 years of age. In male specimens, the flowers are yellowish and appear in axillary groups. In the female, flowers are isolated or in groups of three and are small and white or slightly pink, and consist of four petals and four sepals partially fused at the base. The ‘berry’ fruit is a red drupe, about 6–10 mm in diameter, a bright red or bright yellow, which matures around October or November.

Several varieties and clones are available with different features such as variegated foliage with creamy or pink tinged edges and different leaf shapes. Some of these are:

Ilex aquifolium ‘Alaska’– dark green foliage and bright red berries, can be grown as a standard/ specimen or screening.

Ilex aquifolium ‘Argentea Marginata’– with an Award of Garden Merit, this variety has spiny leaves edged with white and plenty of berries, young leaves tinged with pink.

Ilex aquifolium ‘J.C. Van Tol’– a self pollinating holly and possibly the best green-leaved holly available. Dark green almost sineless leaves witha good show of autumn berries. Also awarded an AGM, it is tolerant of shade.

Ilex aquifolium ‘Pyramidalis’– fast growing, self pollinating. Another AGM winner, it retains its pyramidal shape if pruned to retain it’s leader.

Ilex aquifolium ‘Silver Queen’– this is a dense small evergreen tree or shrub with purple young shoots and pink-tinged young leaves. Mature leaves spiny, dark green with a broad cream margin. Flowers small, white – this variety is, despite it’s name, a male!

Other Ilex varieties that are not part of the aquifolium species include:

Ilex castaneifolia– the ‘sweet chestnut leaved’ holly this is a fast grower, AGM awarded and produces a large tree of conical habit and has red berries in abundance.

Ilex x ‘Dragon Lady’– one of the Meserve Hybrid hollies this one has vivid green leaves and attractive spines that contrast well with the large red berries in the autumn.

Ilex x ‘Nellie Stevens’– this hybrid (of Ilex aquifolium and Ilex cornata) has smooth glossy leaves which contrast well with the orange-red berries.

Ilex x altaclarensis ‘Golden King’ – one of the best variegated hollies, this AGM winner is tolerant of coastal conditions, and is slow-growing. The opposite to the variety ‘Silver Queen’, this time, despite its name it is a female!

Ilex a. ‘JC Van Tol’

Ilex a. ‘Pyramidilis’ new growth

ilex a. ‘Alaska’ flowers

Ilex a. ‘ Silver Queen’

Ilex x altaclarensis ‘Golden King’

Ilex x ‘Dragon lady’ multi stem

Uses:  One of the most evocative and best-loved of all trees; the Common holly is beautiful in its simplicity and brings cheer at the darkest time of the year. It provides year-round interest, but is particularly attractive in autumn and winter. great for gardens, it only retains its spiky leaves within the first ten – fifteen feet of height in the tree, as after this it suffers no predation so has no need of a thorny defence system! use as an under storey or edge fo woodland tree  (as here at Old School Garden), as a specimen (especially those with interesting foliage), for hedging/ screening or as a structural element in mixed borders to provide all-year round interest. Can also be topiarised to provide simple but effective shapes in formal settings.

 Growing conditions: Holly is very tolerant of shade and prefers well-drained soils.

Clipped hollies at Hatfield House, Hertfordshire

Further information:

Wikipedia- Ilex

Wikipedia- Ilex aquifolium

RHS- Ilex aquifolium

RHS- Ilex aquifolium ‘Silver Queen’

Barcham trees directory- Ilex genus

7 plants for Winter Wonder

Old School Gardener