Aesculus carnea var. Briotii 'Briotii', red horse chestnut
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Broadleaf Deciduous Trees

Aesculus carnea var. Briotii 'Briotii'

red horse chestnut

Sapindaceae

Hybrid of garden origin; parents native to the Balkans and southeastern United States

At a Glance

TypeTree
HabitSpreading
FoliageDeciduous
Height30-40 feet (9-12 m)
Width20-30 feet (6-9 m)
Maturity18 years

Growing Zones

USDA Hardiness Zones

4 - 8
Zone 4
Zone 5
Zone 6
Zone 7
Zone 8
These zones indicate the coldest temperatures this plant can typically survive.
Frost Tolerancehardy

Key Features

Attracts Pollinators
Attracts Hummingbirds
Deer Resistant
Maintenancelow

Overview

Aesculus x carnea 'Briotii' is a cultivar of red horse chestnut, a hybrid between Aesculus hippocastanum and Aesculus pavia, reaching 30–40 feet (9–12 m) tall and 20–30 feet (6–9 m) wide, with a broadly rounded to oval crown. Leaves are palmately compound with 5–7 leaflets, each 4–8 inches (10–20 cm) long, dark green and glossy above, borne on long petioles. In May through June, upright panicles of flowers 6–12 inches (15–30 cm) tall appear above the foliage; 'Briotii' is selected for deeper ruby-red flowers compared to typical A. × carnea. Fruit are smooth, round capsules approximately 1.5 inches (4 cm) in diameter containing 1–2 shiny brown seeds (conkers), ripening in September through October. All parts of the plant — leaves, seeds, bark, and flowers — are toxic to humans and most animals if ingested; children and pets must not be allowed access to fallen seeds. Bark is smooth and gray, becoming plated with age. Growth rate is moderate, 1–1.5 feet (30–45 cm) per year. In the Pacific Northwest, this cultivar is largely resistant to the leaf blotch disease (Guignardia aesculi) that disfigures Aesculus hippocastanum by midsummer in humid climates, making it a more reliable ornamental choice in wet coastal conditions.

Native Range

Aesculus × carnea is a hybrid of garden origin with no native range. The parent species — A. hippocastanum (native to the Balkans) and A. pavia (native to the southeastern United States) — do not occur naturally in the same region.

Suggested Uses

Aesculus x carnea 'Briotii' is planted as an ornamental specimen in parks, large residential gardens, and public spaces where the flower panicles and bold compound foliage can be appreciated. Provides dense summer shade. Requires a minimum of 20–30 feet (6–9 m) horizontal clearance from structures. Not suitable for planting near playgrounds, pet areas, or locations where children or animals have frequent access to fallen seeds, which are toxic.

How to Identify

Aesculus x carnea 'Briotii' is identified by large palmately compound leaves with 5–7 leaflets and upright ruby-red flower panicles 6–12 inches (15–30 cm) tall in May through June. Fruit are smooth round capsules (not spiny like A. hippocastanum) approximately 1.5 inches (4 cm) across containing 1–2 shiny brown conkers. 'Briotii' has deeper red flowers than the typical hybrid. Distinguished from A. hippocastanum by smoother (not spiny) fruit capsules and red (not white) flowers.

Appearance

Size & Dimensions

Height30' - 40'
Width/Spread20' - 30'

Reaches mature size in approximately 18 years

Colors

Flower Colors

red

Foliage Colors

dark green

Fall Foliage Colors

yellow
brown

Bloom Information

Bloom Period

~4 weeks
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Spring
Blooms May through June, with upright panicles 6–12 inches (15–30 cm) tall of ruby-red flowers appearing above the expanded foliage. Individual flowers are 0.5–0.75 inch (1.5–2 cm) across; panicles last 3–4 weeks. 'Briotii' consistently produces deeper red flowers than seed-grown A. × carnea. Smooth fruit capsules ripen September through October.

Detailed Descriptions

Flower Description

ruby-red

Foliage Description

dark green and glossy in summer; yellow-brown in fall

Growing Conditions

Sun Requirements

Full Sun
Partial Shade
Requires 4-8 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range5.5 - 7.5(Neutral)
357912
Soil Types
loamclaysilt
Drainage
well drained

Water & Climate

Water Needs

Medium

Frost Tolerance

hardy

Time to Maturity

15-20 years

Care & Maintenance

Care Guide

Aesculus x carnea 'Briotii' is established with regular watering for the first 2–3 growing seasons; once established, the tree tolerates moderate drought and average urban soils. Apply 2–3 inches (5–8 cm) of mulch from the drip line inward, keeping it clear of the trunk. Keep fallen seeds and capsules cleaned up from areas accessible to children and pets — the seeds (conkers) contain aescin and other compounds toxic to humans and animals if ingested. 'Briotii' shows good resistance to leaf blotch disease compared to A. hippocastanum, but may develop some browning of older leaves by late summer in wet climates — this is cosmetic and does not affect tree health.

Pruning

Prune during dormancy (November through February). Remove dead, damaged, or crossing branches at the branch collar. The tree develops a naturally rounded crown with minimal corrective pruning needed. Structural pruning of young trees in years 3–10 to establish a clear trunk and well-spaced scaffold branches reduces the need for large corrective cuts later. Avoid pruning in spring or early summer during active growth.

Pruning Schedule

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Maintenance Level

low

⚠️ Toxicity Warning

Toxic to pets and humans