Holly is a small evergreen broadleaf tree with distinctive deep green, spiky, leathery shiny leaves and bright red berries. It is one of Britain’s few native evergreen trees.

Behaviour

Although the trunk of the holly tree can be up to 40-80 cm in diameter, it frequently divides near the ground, giving rise to multiple smaller stems growing close together.

The bark of holly is grey and smooth, becoming fissured with age. The leaves are from 5-12 cm long and 2-6 cm wide, and on the lower part of the tree, have three to seven sharply pointed spines on each margin, that alternate in pointing upwards and downwards. Higher up, the leaves tend to have fewer or no spines. Individual leaves persist on a tree for 2-3 years, and when they are shed (usually in the spring). They take a long time to decay.

Holly is dioecious, meaning that male and female flowers occur on different trees. The tree starts to flower at around 20 years old. Flowers are white with four petals. They bloom between early spring and the beginning of summer, depending on the local climate. Once pollinated by insects (usually bees, attracted by the fragrance of the flowers), female flowers develop into scarlet berries (each containing up to four seeds) which can remain on the tree throughout winter. The seeds are dispersed in the droppings of birds or other animals.

Holly can grow in a huge variety of environments and under numerous conditions. It can grow in light, sandy soil, medium soil, and even heavy, clay soil. It can survive in extremely acidic environments and is also shade tolerant often found as a dominant under-storey plant. The thick cuticle on Holly leaves prevents water loss and protects the plant against the cold.

Holly can also reproduce vegetatively, by means by shoots growing off the root system of a tree. This appears to be more common in dense woodland, where pollination is less likely to occur.

Size

• Height: 8-10 m (typical for Scotland); can reach 25m, but rare in Scotland
• Lifespan: 30-40 years (when growth culminates); can reach an age of 300 years

Status

Least concern

Distribution

Holly, or European holly as it is sometimes known, occurs naturally in western, central and southern Europe, where its range includes the coastal region of Norway, Denmark, Germany, Britain, Ireland, Portugal, Spain and across the Mediterranean to Bulgaria and Turkey.

Holly is a widely distributed native species in Scotland occurring throughout the mainland, except for Caithness. It is also absent from Orkney, Lewis, Harris and Skye.

When to see

January to December

Facts

• Holly berries (and leaves and bark) are mildly toxic because they contain toxins, such as saponin, (a chemical commonly used in soaps and detergents) and phenolic, a compound used in plastics.
• The smoother leaves found at the tops of holly trees are a winter source of food for deer, whilst the berries are a vital source of food for birds, especially thrushes. The mistle thrush is known for vigorously guarding holly berries to prevent other birds from eating them.
• Before the advent of the Victorian Christmas pine tree, holly branches had been used as decoration since Roman times. Today, holly still plays an important part in Christmas celebrations, its name being heard in many Christmas songs.
• In Britain, it is believed to be very bad luck to cut down a Holly tree.