Holly

Holly: how do you recognise it?

Habit

Evergreen shrub or small tree of 3–15 m, often narrowly conical; as a hedge it can be clipped dense.

Leaf

Alternate, evergreen, leathery and glossy dark green, 5–10 cm; wavy edge with sharp spines. Higher up the tree the leaves are often spineless.

Bark

Smooth and grey, even on old trees.

Flower

Small white flowers in May–June; male and female flowers grow on separate plants.

Fruit

Red berries on female trees, from autumn into spring. Poisonous to humans.

Difference from cherry laurel

Cherry laurel has a larger leaf (10–20 cm) without spines.

Flowering: May · Pruning: March–April and July–August

Identify by feature: Spiny leaves · Evergreen leaves · Red berries

Looks like it, but isn’t

• Cherry laurel Prunus laurocerasus: larger leaf without spines. Difference from cherry laurel

Why grow it?

• One of the few native evergreens: green all year round, even in deep shade.
• A prickly evergreen hedge that keeps out unwanted visitors.
• Red berries in winter: food for thrushes and blackbirds, and Christmas greenery for indoors.
• Dense cover and safe nesting places for birds.
• Grows on almost any soil, in sun, partial shade or shade.

Holly: where does it grow best?

• Sun, partial shade or shade: holly is a true shade plant, but in sun it flowers more freely and bears more berries.
• Almost any well-drained soil; no waterlogging or ground that stays flooded for long.
• It feels at home under large trees such as beech and oak.
• Allow 4–5 m width for a free-standing tree; as a hedge it fits in any garden.

Light

Sun to shade

Legal basis

Any garden soil

Moisture

Normal

Size

12 m tall, 5 m wide

Hardiness

Throughout Belgium, no protection needed

Goes well with

• Beech: Holly likes to grow in the shade of beech: winter green under a bare crown.
• English oak: Holly feels at home in the understorey of an oak wood or woodland edge.
• Common ivy: Another native evergreen for shade; together they feed the holly blue butterfly.
• Yew: Evergreen and shade-tolerant: together a dense, mixed hedge.

Good and bad companions

Goes well with

• Together a mixed native hedge, good for birds and insects: hawthorn, blackthorn, hazel, dog rose, common dogwood, guelder rose, wild privet, field maple
• Tolerate the shade under this tree: oregon grape, rhododendron, oleaster, japanese skimmia, garden privet, camellia, laurustinus, box-leaved honeysuckle

Holly: when and how to plant it?

1. Plant in early autumn (September–October) or in spring (April), root-balled or container-grown: holly does not like being moved bare-root.
2. If you want berries, plant a female with a male nearby, or choose a self-fertile variety such as ‘J.C. van Tol’.
3. For a hedge: 2–3 plants per metre.
4. Dig a generous planting hole, mix in some compost and set the plant at the same depth as before.
5. Water generously after planting and during dry spells in the first year: an evergreen loses water in winter too.

Care

Watering

Regularly in dry spells during the first year; rarely needed after that.

Feeding

A little compost or leaf mould in spring; nothing more is needed.

Mulch

A layer of leaf mould or wood chips keeps the soil cool and moist, as in woodland.

Fallen leaves

Old holly leaves drop mainly in spring and stay prickly for a long time: rake them up near paths, lawns and sandpits.

Tip: Is the holly going near a path, a seating area or a play corner? Then choose a variety with few spines, such as ‘J.C. van Tol’.

Holly: when to prune it?

Pruning months: March–April and July–August.

When: Clip a hedge in summer (July–August). Formative pruning or renovation in late March–April.

How:

• Holly regrows well, even after hard pruning: an overgrown or bare shrub can be cut back hard.
• Ideally cut branches one by one with secateurs; a hedge trimmer cuts leaves in half and they turn brown.
• Renovate an old hedge over two years: one side in the first year, the other side the next.
• On a variegated holly, remove all-green shoots right back to their base.

Caution: Wear sturdy gloves against the spines, and don’t prune while birds are still nesting in the shrub.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Cuttings

In late summer or autumn, take semi-ripe cuttings of 10–15 cm and root them in a pot of sandy compost, under glass or plastic. A cutting is male or female, just like its parent.

Layering

Bend a low branch down to the ground, nick it lightly and cover it with soil; after a year you can cut it free.

Sowing

Take the seeds from ripe berries and sow them outdoors in a pot; they germinate slowly, often only after a year and a half. Only after several years will you know whether a seedling is male or female.

Holly: how does it get through the winter?

Hardy throughout Belgium: no protection needed.

• Fully hardy.
• In severe frost with a cold east wind the leaves can scorch brown, especially on variegated forms and young plants; the plant grows back in spring.
• The berries often stay on until spring, unless thrushes and blackbirds eat them first.

Diseases and pests

• Holly leaf miner: Yellow to brown blotches in the leaf, caused by a larva living inside. Harmless; cut off badly affected twigs.
• No berries: A male plant never bears berries, and a female only with a male nearby. Look at the flowers: male ones have stamens with pollen, female ones a green ovary.
• Scale insects: Small brown scales under the leaves and on the twigs, with sticky honeydew and black sooty mould. Brush them off or cut out affected twigs.
• Root rot: Yellow leaves and dying branches on wet, poorly drained soil. Plant holly in a well-drained spot.

Through the year

• January: Thrushes and blackbirds eat the berries; leave them on.
• March: Late March: formative pruning or renovation of shrub or tree.
• April: Formative pruning and renovation; plant root-balled or container-grown holly.
• May: Flowering; old leaves drop: rake them up near paths.
• June: Check for leaf miner and scale insects.
• July: Clip the hedge, once birds have stopped nesting.
• August: Clip the hedge; take semi-ripe cuttings.
• September: Plant root-balled or container-grown holly; take cuttings.
• October: The berries turn red; planting season continues.
• December: Christmas greenery: cut a few berried sprigs sparingly and leave the rest for the birds.

What can you use it for?

Garden and landscape

Prickly evergreen hedge (keeps out unwanted visitors) and Christmas greenery.

For wildlife

Berries as winter food for thrushes and blackbirds; dense cover for birds.

Wood

White, hard wood for inlay and chess pieces.

Caution: The berries are poisonous to people.

Good for wildlife

Birds

Berries, seeds or insects as food, or a place to nest.

Caterpillars

Host plant: caterpillars of butterflies or moths eat the leaves.

Bees

Nectar and pollen for honeybees and wild bees.

Did you know?

• Likes to grow in shade under beech and oak, and is a classic Christmas decoration.
• Its white, hard wood was used for inlay and chess pieces.
• In spring the caterpillars of the holly blue feed on holly flower buds; those of the summer generation live on ivy.
• The holly blue, a small blue butterfly, lays its eggs on holly flower buds in spring; the summer generation mostly chooses ivy.
• The yellowish blotches often seen in holly leaves are the work of the larva of a small leaf-mining fly (Phytomyza ilicis), which feeds inside the leaf.