Eucalyptus regnans
Australian mountain ash
Overview
Eucalyptus regnans is an evergreen tree reaching 200-330 feet (60-100 m) tall, with a straight trunk up to 10-16 feet (3-5 m) in diameter and a high, open crown. The lower trunk carries a stocking of rough, fibrous brown bark, above which the bark is smooth, grey to cream, and sheds in long ribbons. Adult leaves are lance-shaped, 3.5-6 inches (9-15 cm) long, glossy green, and held alternately. White flowers about 0.6 inch (1.5 cm) across open in clusters of 9 to 15 in summer and autumn, followed by small woody capsules about 0.3 inch (7 mm) long. It grows fast in youth, adding 3-6 feet (0.9-1.8 m) a year on good sites, and can exceed 60-80 feet (18-24 m) within 20 years. Unlike many eucalypts, it is killed by intense fire rather than resprouting, and regenerates densely from seed. It needs cool, moist mountain conditions with deep, fertile soil and high rainfall, and grows poorly on dry, exposed, or low-rainfall sites.
Native Range
Native to southeastern Australia, in the cool, wet mountain forests of Victoria and Tasmania. Grows in deep, fertile soils in high-rainfall areas above about 1,000 feet (300 m), often in tall, dense stands. Restricted to sites with reliable moisture and protection from frequent fire.Suggested Uses
Used in forestry, catchment plantings, and large parklands in cool, high-rainfall areas, spaced 20-50 feet (6-15 m) apart. Suited only to large, open sites with room for a very tall tree and falling bark and limbs. Too large and moisture-demanding for small or dry gardens.How to Identify
Appearance
Size & Dimensions
Height200' - 330'
Width/Spread50' - 80'
Reaches mature size in approximately 30 years
Bloom Information
Flowers in summer and autumn, mainly February to May in its native range, though heavy flowering occurs only every few years. The white flower clusters open over several weeks and draw insects and nectar-feeding birds. Capsules ripen over the following months and release seed after fire or branch fall.
Detailed Descriptions
Foliage Description
glossy greenGrowing Conditions
Sun Requirements
Requires 6-12 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
Care & Maintenance
Care Guide
Grows in full sun on deep, fertile, moisture-retentive soils in cool, high-rainfall districts. Water young trees through dry spells; the species has little drought tolerance and declines on dry or exposed sites. It grows without supplementary feeding on suitable soils. Defoliating insects and fungal leaf diseases occur in some seasons. It is killed by intense fire and does not resprout, so stands regenerate from seed. Trees grow fast in youth and reach great size, which limits their use to large, open sites.Pruning
Remove low and competing branches in the early years to form a single clear trunk; large eucalypts respond poorly to heavy topping, which produces weak regrowth. Formative pruning is done while branches are small. Mature trees need little pruning beyond removal of deadwood.Pruning Schedule
J
F
M
A
M
J
J
A
S
O
N
D
winter