The cheery, festive berries of the holly cause vomiting if eaten by humans. The leaves are not toxic though, and are used in drinks across the Americas, as many contain caffeine. One species, Ilex guayusa, has the highest caffeine content of any plant.
Holly (Ilex aquifolium)
- Scientific name: Ilex aquifolium
- Family: Aquifoliaceae
- Place of origin: western Asia, northern Africa, southern and western Europe.
- Conservation status: common and widespread, not considered a conservation concern.
- Date planted: unknown
- Height: 6.5 m
About Kew's holly trees
Many species and cultivars of Ilex can be seen growing along Holly Walk, which runs behind the Evolution House, ending at Cedar Vista. Holly Walk is one of Kew's historic features, and is planted along what used to be Love Lane, which formed a public right of way from Kew to Richmond. The plants along Holly Walk represent one of the largest, most complete collections of mature hollies in the world. The collection is well-studied, having been worked on by Kew taxonomists since 1976.
Take a closer look
- Look higher up the tree. It seems the leaves' spikes are protection for the tree against foraging animals, as those higher up the plant have fewer spines.
Left untrimmed, a mature holly tree will grow to 20 metres, although many are smaller and more shrub-like. It is is a hardy tree, capable of surviving in most conditions except where it is extremely wet. Large circular groves of holly trees tend to form in the wild – the outer branches touch the ground and take root, then the original central tree eventually dies. Examples of this can be found in the New Forest in Hampshire.
Cultivation and uses
This evergreen, with its glossy bright foliage and scarlet berries, is a renowned Christmas decoration of centuries' standing. The density of spiky foliage means that holly also lends itself perfectly to the world of home security. It is therefore widely planted as a hedge or ornamental. Freshly cut holly burns fiercely and makes excellent firewood as oils found in the thick skin of the leaves produce a flammable vapour when heated.
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