Eucalyptus regnans (Mountain Ash)


Botanical Information

FamilyMyrtaceae
GenusEucalyptus
Speciesregnans
CategoryWoody
TypeTree (evergreen)
OriginNative to Tasmania and Victoria, Southeast of Australia.
Ethnobotanical Uses
Disclaimer
Used for making essential oils. Also used commonly for its valuable lumber. Be careful, as the oils can be toxic to some animals.

Details

USDA Hardiness Zone8 - 11
USDA Hardiness Ref.
Canadian Hardiness Zone8b - 9b
Canada Hardiness Ref.
RHS Hardiness ZoneH4
RHS Hardiness Ref.
Temperature (°C)21
Temperature (°F)70
Height90 m
Spread8 - 30 m
GrowthSlow
Flowering PeriodMarch, April, May

Description and Growing Information

General DescriptionMassive upper storey tree. It is one of the largest/tallest species of all Evergreen trees and the Eucalyptus genus in particular.
ID CharacteristicThe tallest of all tree species. Peeling bark resembles strains of ribbons.
ShapeTall, upright growing pattern with a narrowed open canopy.
LandscapeIt is an important tree for wildlife. An example would be koala bears, as the leaves they chew on provide a great food source and contain the right amount of nutrients. Bees are also attracted to this tree due to its huge pollination benefits.
PropagationBe sure to sow your seeds in early spring. Temperatures should be 4.4°C for 2 months approximately. Germination temperature should be around 21.1°C and 29.4°C. Germination will take anywhere from 2 to 4 weeks.
CultivationPrefers full sun to partial shade. Rich, moist, well-drained soils. Avoid exposed locations. It is tolerant to frost and drought. It is encouraged to plant where deep rooting is susceptible and it can have good stability for long term care. Acceptable soil pH is mildly acidic to mildly alkaline (4-6 on the pH scale). Sandy, loamy and clay soils are also suitable for this hardy tree. Does not prefer to grow fully in shade.
PestsDiseases include: Aulographina eucalypti, leaf spot with a corky appearance. Mycosphaerella cryptica, red to brown distorted leaves with a purple margin. Mycosphaerella swartii, small purple-red leaf spots. Phaeophleospora microthyrioides, yellow leaf discoloration with black fruit bodies. Phaeophleospora eucalyptorum, another form of brown leaf spots, occurring on new foliage growth. Trimmatostroma bifarium, lesions of black powdery masses. Pests are not particularly a problem with E. regnans.
Notable SpecimensSouthwest National Park and Mount Field National Park. They can be found growing in the Tasmania Forest landscapes.
HabitatFound growing in in the foothills/mountain regions of Tasmania and Victoria in Australia. Seen mostly in vast forest landscapes.
Bark/Stem DescriptionThe bark is rough for the first 15 m of growth. The colour is usually grey, black or brownish. This is accompanied by a crumbly appearance. Above 15 m, the bark texture will have a nice smooth look, followed by a cream or olive-grey colour. The bark will shed in a ribbon like fashion.
Flower/Leaf Bud Description2-3 mm long, 3-4 mm wide. Buds are a conical shape. Each umbel will have 9 to 15 buds. Mature buds are obovoid in shape, 0.4 to 0.7 cm long, 0.2 to 0.4 cm wide. The colour can range from yellow, green, to brown.
Leaf DescriptionMature leaves are alternate in shape. The petiole is 0.8 to 2.5 cm long. Lance-shaped in appearance and curved at the tip. These are 9 to 15 cm long and 1.5 to 5 cm wide. The colour is usually a glossy green, with acute side-veins. Young leaves are opposite in shape, then will begin to alternate. The leaves are 5.5 to 12 cm long and 2.2 to 5 cm wide. Colour is glossy green and will retain through its maturity.
Flower DescriptionFlowers are small (1.2 cm), white in colour. Blooming through March until May. They can be seen in clusters with about 9 to 15 flower buds. These flowers also make a great crop for bees.
Fruit DescriptionThe fruit growing on pedicels is 0.1 to 0.7 cm long. Can be cup-shaped or have a conical appearance to them. When the fruit is more mature, it is 0.5 to 0.8 cm long and 0.4 to 0.7 wide. The disc (tissue in-between the bud) will descend slightly. Valves (sectors/roof of fruit) are mostly enclosed or near rim level.
Colour DescriptionFoliage will remain green throughout the seasons. Flowers are white. Bark is a greyish brown colour.
Texture DescriptionCoarse throughout the seasons.

Photographs