Holly is the common name for plants in the genus Ilex, a large group of evergreen and deciduous shrubs and trees. Many species are immediately recognisable by their glossy, leathery leaves and clusters of brightly coloured fruit. Hollies are used widely in gardens and parks for their year-round foliage and as focal shrubs in temperate landscapes. For a general overview and images, see holly.

Characteristics

Leaves are usually simple, alternately arranged and often have spiny or toothed margins, although some species have smooth edges. Many hollies retain their leaves through winter because the foliage is thick and protected by a waxy cuticle that reduces water loss. Small, usually white or pale flowers appear in spring or early summer. The fruit are fleshy drupes — commonly called berries — that range in colour from red to orange or black and persist into winter on many female plants.

Biology and reproduction

Most hollies are dioecious, meaning individual plants produce either male or female flowers; only female plants set fruit when pollen from a male plant is available. The berries attract birds and other wildlife, which consume the fruit and disperse the seeds. Hollies occur across temperate and subtropical regions of the world and comprise several hundred species with a variety of growth forms and leaf types.

History, cultural use and horticulture

Holly has long been associated with winter festivals and wreath-making in Europe and beyond; its evergreen leaves and colourful fruit made it a popular decorative plant in cold months. Gardeners prize species such as the English holly for hedging, specimen planting and topiary, and many cultivars have been selected for leaf variegation, compact habit or abundant fruit. Wood from some hollies is dense and has been used for small carvings and turned objects.

Uses, cautions and notable species

Certain species of Ilex have been used to make stimulating or herbal infusions. Well-known examples include Ilex paraguariensis (yerba mate), Ilex guayusa, and some traditional preparations from Ilex vomitoria; these are the basis for regional beverages and are sometimes described broadly as holly-based teas. While berries feed birds in winter, many hollies’ fruits are mildly toxic to humans and pets and can cause nausea or vomiting if eaten in quantity, so they should not be consumed indiscriminately.

  • Distinctive features: glossy leaves, waxy surface, often spiny margins.
  • Reproduction: dioecious plants — need male and female individuals for fruit.
  • Ecological role: fruit important for birds during scarce months.
  • Cultivation: used for ornament, hedges, and select cultivars for winter interest.