Red buckeye

Red buckeye: how do you recognise it?

Habit

Small tree or large shrub, often multi-stemmed, 5 m tall and 4 m wide, with a rounded crown.

Leaves

Palmate, usually made up of 5 leaflets of 10–15 cm; dark green, glossy and finely toothed; unfolding early in spring.

Flower

Upright candles of 10–20 cm with tubular, deep red flowers, in May–June.

Fruit

Smooth, leathery capsule holding 1–2 glossy brown seeds with a pale scar.

Roots

Deep and widely branching; transplanting works best as a young tree.

Flowering: May–June · Plants: March–April and October–December · Pruning: January–February

Why grow it?

• Deep red flower candles in May–June, a rare colour in trees.
• Stays small (about 5 m tall and 4 m wide) and suits a smaller garden.
• The flowers attract bees and bumblebees.
• Attractive glossy foliage that unfolds early in spring.
• Fully hardy and easy in most garden soils.

Red buckeye: where does it grow best?

• Sun or partial shade; it tolerates some shade but flowers most in sun.
• Moisture-retentive, humus-rich soil: sand, loam or clay, acid to neutral (not too chalky).
• Normally moist; in hot, dry summers the leaves may scorch or drop early.
• Allow 4–5 m of space all round, far from houses, drains and paving.
• Sheltered from strong wind; avoid a very dry, sun-baked spot.

Light

Sun and partial shade

Soil type

Sand, loam or clay

Acidity

Acid or neutral

Moisture

Normal

Size

5 m tall, 4 m wide

Hardiness

Hardy (to -25 °C)

Goes well with

• Rhododendron: Likes the same acid soil and partial shade under the crown.
• Hydrangea: Flowers later in summer, after the buckeye has finished.
• Hosta: A foliage plant for the shade under the tree.
• Ferns: A fresh, green underplanting beneath the crown.

Red buckeye: when and how to plant it?

Plant in March–April and October–December.

1. Plant in October–December or March–April, when the soil is neither frozen nor too wet. Bare-root trees in November–March.
2. Dig a hole two to three times as wide as the root ball and loosen the sides and bottom.
3. Set the tree at the same depth as in the pot or nursery and backfill with the soil you dug out, mixed with a little compost.
4. Drive in a sturdy stake and tie the trunk loosely; check the tie every year.
5. Water thoroughly when planting and then in dry weather for 2–3 summers.
6. Lay a mulch ring 5–8 cm deep of compost or leaf mould, kept away from the trunk.

Care

Water

For the first 2–3 years, water thoroughly 1–2 times a week during long dry spells. An established tree usually looks after itself, but extra water is still welcome in hot summers.

Feeding

Usually not needed. A thin layer of compost in spring is enough on poor soil.

Mulching

A mulch ring keeps the soil moist and cool; keep the trunk itself clear.

Support

Young trees get a stake for the first 2–3 years, which you then remove.

Leaves and fruit

Clear fallen leaves and seeds in autumn: it limits leaf diseases and stops children or pets picking them up.

Tip: A small horse chestnut for smaller gardens, with deep red flower spikes in May–June. All parts, especially the seeds, are poisonous.

Red buckeye: when to prune it?

Pruning months: January–February.

When: As little as possible. If needed between January and February, in the dormant season, in dry, frost-free weather.

How:

• Remove dead, damaged and crossing branches.
• Train it as a tree with a single trunk, or let it grow as a multi-stemmed shrub and remove the weakest stems at the base.
• Saw large branches off in three steps, just outside the branch collar, so that the wound can heal.
• Do not prune too hard: a natural, rounded crown looks best.

Caution: Do not prune in wet weather and avoid unnecessary wounds: horse chestnuts are susceptible to bleeding canker.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Sowing

Sow fresh seeds in October–November directly outdoors, 5 cm deep, protected from mice and squirrels. They germinate in spring; the young trees grow slowly. Seedlings do not always resemble the parent plant.

Grafting

Cultivars such as ‘Atrosanguinea’ are grafted by nurseries; this is not a job for the ordinary gardener.

Red buckeye: how does it get through the winter?

Hardy to −25 °C.

• Fully hardy, down to about −25 °C: no protection is needed, even in harsh Belgian winters.
• Young trees: leave the stake in place and add an extra layer of mulch around the base in the first year.
• Clear fallen leaves and seeds; do not leave a thick mat of wet leaves around the trunk.

Diseases and pests

• Scorched or dropping leaves: In hot, dry summers the leaf edges turn brown and the leaves drop early. Water young trees enough, mulch and avoid a very dry, sunny spot.
• Powdery mildew: White powder on the leaves in late summer, especially in dry weather. Usually harmless; make sure it gets enough water and clear the fallen leaves.
• Leaf blotch: Brown patches with a yellow edge on the leaves in wet summers. Usually harmless; clear the fallen leaves.
• Bleeding canker: Reddish-brown, slimy patches on the bark and dying branches. There is no simple cure; cut affected branches off in dry weather and call a tree surgeon if the trunk is affected.

Through the year

• January: Prune if needed (dead wood). Check young trees after wind and frost.
• February: Prune if needed. Check the tie and stake.
• March: Plant (container trees). Mulch.
• April: Plant. Leaves unfold early. Water the young tree in dry weather.
• May: Flowering begins. Bees and bumblebees on the flowers.
• June: In flower. Water young trees in dry weather.
• July: Water in dry weather. Watch for leaf scorch.
• August: Watch for mildew and drought damage; early leaf drop is possible.
• September: Seeds ripen and fall. Autumn colour begins.
• October: Collect seeds and sow if you like. Clear leaves. Plant.
• November: Plant (bare-root too). Clear the last leaves.
• December: Plant if the soil is open. Rest.

Edible and useful

Not edible. Buckeyes and horse chestnuts are poisonous in all their parts, especially the shiny brown seeds: they cause vomiting, stomach ache and diarrhoea. Children take them for sweet chestnuts, but those come two or three to a husk covered in fine, sharp spines, with one flat side and a pointed tip ending in a little tuft; these seeds sit in a smooth husk, are round and have a large pale patch. Dogs that chew them become ill, and a swallowed seed can block the gut. Pick up the seeds where children or animals play, and do not plant them next to a field with horses or livestock. 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.

Did you know?

• The red horse chestnut (Aesculus × carnea), often planted in parks, is a cross between the common horse chestnut and the red buckeye.
• The name ‘buckeye’ refers to the glossy brown seeds with a pale scar, which look like the eye of a deer.
• The species name pavia honours Pieter Paaw (Petrus Pavius), a Dutch botanist of the 16th–17th century.