Ilex aquifolium aka Holly

Ilex aquifolium is known as English or common holly. This evergreen tree belongs to the holly family, Aquifoliaceae. It comes from Europe, North Africa, and western Asia. It is native to Britain and Ireland as well. Wild plants grow in scrub, hedges, and woodland. They can form a dense layer beneath taller trees. The species has spread beyond gardens in the Pacific Northwest. Some western US states list it as invasive.

Garden trees reach 30–50 feet (9.1–15.2 metres) tall. Their spread reaches 15–25 feet (4.6–7.6 metres). Some trees reach 80 feet (24.4 metres). Pruning can keep shrubs at 10–15 feet (3–4.6 metres). Growth is slow, and branches form a dense pyramid. The smooth bark ranges from grey to black. Leaves grow in an alternate pattern along the shoots. They are dark green, glossy, leathery, and oval. Their wavy edges bear sharp spines. Young leaves have more spines than mature ones.

Small, scented flowers open in spring, often during May. They range from white to greenish white. Bees pollinate them, though the blooms draw little visual attention. Male and female flowers grow on separate plants. Female plants need a nearby male to set fruit. The small, berry-like drupes ripen from late summer into fall. Most are red, but some are orange or yellow. They can stay on the branches through winter. The fruit draws birds and adds winter colour.

Grow holly in sun or part shade with good drainage. It prefers moist soil and tolerates several soil types. These include clay, loam, sand, and chalk. It accepts acid, neutral, and alkaline soils. Shelter from cold winter winds helps protect the plant. Give it afternoon shade where summers are hot. Hot, humid summers and harsh winters can limit its growth. Sources place it in USDA zones 7–9 and UK H6. Use it as a specimen, tall hedge, or screen. Its foliage also serves as Christmas decoration. Its hard, dense wood has value for cabinet work.

Scale insects, leaf miners, and aphids may attack holly. Wet soil can lead to root rot and leaf disease. Other risks include cankers and honey fungus. Leaves have served as tea substitutes, and roasted fruit as coffee substitutes. These past uses do not make it safe to eat. The fruit contains toxic saponins and can harm people. Leaves and fruit also poison dogs, cats, and horses. Eating them can cause vomiting, diarrhoea, and depression.