Italian buckthorn

Italian buckthorn: how do you recognise it?

Habit

Dense, bushy, evergreen shrub about 3 m tall and 2.5 m wide; in the wild it can grow taller and take a small tree form.

Foliage

Alternate, leathery, glossy dark green leaves, oval to lance-shaped, 2–5 cm long. No thorns.

Flower

Small yellow-green flowers in short clusters in March–April; not showy. Plants are usually either male or female.

Fruit

Small berries, red at first, then black, on female plants only. Toxic to people and pets.

Variegated form

‘Argenteovariegata’ has a cream-white edge around the green leaf and is the most widely sold form.

Flowering: March–April · Plants: April–May and September–October · Pruning: June

Why grow it?

• Glossy green all year, even in winter when few shrubs carry leaves.
• Tolerates sun and drought once established: a shrub for dry, sunny places.
• The variegated form brings light to a green border or hedge.
• Flowers as early as March–April, when bees and other insects find little food; the berries feed birds.
• Easily clipped into a dense hedge, a ball or a free-standing shrub.

Italian buckthorn: where does it grow best?

• Sun to half shade; the variegated form keeps its pattern best in sun.
• Well-drained soil: sand, loam or clay, acid to chalky. Dry soil is no problem, heavy waterlogged clay is.
• Choose a sheltered spot, for example against a south- or west-facing wall: cold, drying east winds in winter damage the leaves.
• Allow 2–2.5 m for a specimen; for a hedge, plant every 80–100 cm.

Light

Sun and partial shade

Soil type

Sand, loam or clay

Acidity

Not fussy

Moisture

Dry or normal

Size

3 m tall, 2.5 m wide

Hardiness

Hardy (to -15 °C)

Goes well with

• Lavender: Same sun and dry soil; its grey-green mounds contrast with the glossy leaves.
• Rosemary: Another evergreen shrub for the dry, sunny border.
• Rock rose (Cistus): Flowers freely in summer in the same dry, sunny conditions.
• Feather grass: A light ornamental grass that softens the firm foliage.

Italian buckthorn: when and how to plant it?

Plant in April–May and September–October.

1. Plant in April–May or September–October; in spring it has the whole summer to root before its first winter.
2. Dig a hole twice as wide as the root ball and as deep, and loosen the sides. On heavy clay, mix some sand into the soil.
3. Set the plant at the same depth as in its pot, with the root collar at soil level, and firm the soil well.
4. Water thoroughly straight away, even if it is raining.
5. Spread a 5 cm layer of mulch (wood chips or bark) around the base, keeping it clear of the stem.

Care

Water

In the first year, give a good watering every week in dry weather. After that it rarely needs extra water, only in long dry spells.

Feeding

Usually not needed. On poor soil, a handful of organic fertiliser or some compost in April.

Mulching

Wood chips or bark keep the roots cool in summer and give a little extra protection in winter.

Wind and frost

Shelter it from cold east winds and wait until growth restarts before removing damaged parts.

Berries

Female plants carry berries. Leave them for the birds, but cut them off if small children play in the garden.

Tip: Plant it against a south- or west-facing wall and prune in June: the new growth then has time to harden off before winter and it survives frost much better.

Italian buckthorn: when to prune it?

Pruning months: June.

When: In June, once the spring growth is finished and late night frosts are over.

How:

• Shorten the shoots to the shape you want, always just above a leaf or side shoot.
• Trim a hedge with shears or a hedge trimmer, slightly narrower at the top than at the base so light reaches the bottom.
• Remove dead, damaged and frosted branches. After frost damage, wait until new shoots appear in May.
• Renovate an overgrown shrub in stages over two years, not all at once.

Caution: Do not prune late in the season: late shoots do not harden off and are easily killed by winter frost.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Semi-ripe cuttings

From July to September: take 10–15 cm cuttings of this year’s shoots, remove the lower leaves and insert in a mix of sand and potting compost under plastic. They root slowly, so be patient.

Seed

In autumn, take the seed from ripe black berries (wearing gloves) and sow it in a pot outdoors, so winter cold helps it germinate. Seedlings do not always resemble the variegated parent.

Italian buckthorn: how does it get through the winter?

Hardy to −15 °C: protect young plants.

• Hardy to about −15 °C. In Flanders it usually copes in a sheltered spot, but in severe frost the leaves may turn brown.
• Protect young plants for the first two winters: a layer of leaves or mulch around the base and, in severe frost, horticultural fleece over the crown.
• After frost damage it often shoots again. Only cut away what is clearly dead in May.
• In a pot: stand it against a wall, wrap the pot in hessian or bubble wrap and move it to a frost-free place in severe frost.

Diseases and pests

• Frost damage: Brown, limp leaves after a hard winter or cold east wind. Choose a sheltered spot, do not feed late in the season and wait until May to cut back.
• Root rot: Yellow, drooping leaves on soil that is too wet. Improve drainage with sand or plant on a slight mound; do not overwater.
• Scale insects: Small brown shields on stems and leaves, with sticky honeydew. Wipe them off with a soft brush and soapy water; many natural enemies help.
• Aphids: Clusters of aphids on young shoots in spring. Rinse them off with water or let ladybirds do the work.

Through the year

• March: Flowering begins. Check for frost damage, do not prune yet.
• April: Flowering. Plant or move, apply mulch.
• May: Plant. Water young plants regularly. Check new shoots after frost damage.
• June: Prune and shape.
• July: Water young plants in prolonged drought. Take semi-ripe cuttings.
• August: Semi-ripe cuttings. Berries turn from red to black.
• September: Plant. Collect ripe berries for sowing.
• October: Plant. Top up the mulch and protect young shrubs.
• December: Rest. In severe frost, cover young plants with fleece.

Edible and useful

Not edible. The berries of this buckthorn, first red and later black, are poisonous, and the leaves and bark are not for eating either: like the native buckthorn (Rhamnus cathartica), it contains laxative compounds that cause stomach ache, vomiting and diarrhoea, in children as well as in dogs and cats. Only female plants bear berries, but in a hedge or against a wall they are often at a child’s height. Teach children that they are not for eating, pick them off where small children play, and keep dogs and cats away from fallen berries. Birds, however, eat them without harm. If any is swallowed, call a poison centre (in Belgium 070 245 245) or your doctor at once.

Good for wildlife

Bees

Nectar and pollen for honeybees and wild bees.

Birds

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

Did you know?

• The native purging buckthorn (Rhamnus cathartica) has thorn-tipped twigs; this southern species has no thorns.
• Male and female flowers are usually on separate plants; only female plants bear berries.
• In the Mediterranean it is a typical shrub of the scrub, and after a fire it often resprouts from the roots.