Eucalyptus pulverulenta compacta 'Baby Blue' Silver-leaved Mountain Gum
Eucalyptus pulverulenta compacta 'Baby Blue' trees are growing as feature plants in front of the stone walls between the Village Centre and Pod Playground to the north and outside the National Bonsai and Penjing Collection to the south.
Other common names
Silver Dollar Tree
Origin of the species name
Eucalyptus is from Greek eu kalyptos, meaning well-covered, referring to the cap that covers the buds, which lifts off as the flowers open; pulverulenta is from the Latin word pulverulentus, meaning full of dust, dusty or powdery. The leaves, young stems and inflorescences of E. pulverulenta have a powdery white bloom.
This is a distinctive evergreen tall shrub or small compact tree with smooth, grey to bronze bark which sheds in long ribbons. In cultivation the species is usually seen as a tall, spreading shrub. It is an unusual Eucalypt because it retains its distinctive, round to heart-shaped, paired, waxy, blue-green juvenile leaves into maturity. The juvenile leaves are 5 cm long and wide. Only rarely are adult leaves produced, these being stalked, oval to lance shaped, dull grey-blue in colour, and grow to 10 cm in length and 2 cm in width. The stalkless, large cream-coloured flowers occur in clusters of three. Flowering occurs between May and November. Flowers are followed by large, cylindrical or hemispherical, grey-blue gumnuts, which are also stalkless and grow to 5–8 mm in length and 6–8 mm in diameter. Fruits have flattened discs and valves to rim-level or protruding. Height 6m Spread 5m.
In the early 1970s, a Northern California nursery happened upon a unique selection of this bluish-grey small tree; it is now registered as Eucalyptus pulverulenta ‘Baby Blue’ and has spread via the cut flower industry around the world.
Natural distribution and habitat
Eucalyptus pulverulenta is a rare tree in the wild with restricted distribution, native to New South Wales in Australia. Ten natural populations of the species are known, with approximately 5400 plants in total. There are several small stands in the Bowenfels district on the NSW Central Tablelands (Lithgow to Bathurst area), and a few occurrences on the NSW Southern Tablelands (Bredbo and Bombala areas). The Southern Tablelands populations generally occur over larger areas than the Central Highlands stands, although the distribution is sparse.
Populations occur on the crests or upper slopes of moderately steep hillsides or mountains at altitudes of 800–1000 m usually on well-drained skeletal soils with frequent rock outcrops. The southern populations occur in sandy or gravelly loams over shales and sedimentary rock. The species is usually an understorey plant in open forest or woodland with a canopy height of 5–10 m, typically dominated by Brittle Gum (Eucalyptus mannifera), Red Stringybark (E. macrorhynca), Broad-leafed Peppermint (E. dives), Silvertop Ash (E. sieberi), Inland Scribbly Gum (E. rossii), Red Box (E. polyanthemos), Long-leaved Box (E. goniocalyx), and Apple Box (E. bridgesiana). Plants also occasionally occur in Acacia - Callitris low woodland.
In the past the species distribution may have been more widespread with populations occurring between the north and south occurrences.
The species is classified as vulnerable in its natural habitat, mainly because of damage to habitat by grazing and trampling, especially by domestic stock and feral goats (Capra hircus), which impact on recruitment, damage or clearing for fire trails or development, increasing fragmentation and loss of habitat and illegal seed collection.
Peters and colleagues (1990) undertook a study of the genetic variation of the Silver-leaved Mountain Gum populations. The study concluded that the two largest populations (at Mt Blaxland in the Blue Mountains and Schofields Creek near Bredbo) are the most genetically diverse, and their conservation is therefore of prime importance. This finding is in addition to the Inaloy Fire Trail population, which also contains significant genetic variants. This latter population also exhibited a more robust appearance than other populations, as one tree carried some lanceolate 'adult'-like leaves not seen elsewhere during the study.
Not planted in a forest but a small number of individual trees are growing as feature plants in front of the stone walls between the Village Centre and Pod Playground to the north and outside the National Bonsai and Penjing Collection to the south.
In Australia the Silver-leaved Mountain Gum is grown commercially as an ornamental and for cut foliage for the florist industry, where it is known as "Florists Silver Dollar. The species was probably introduced to California from NSW in the second half of the 1800s from an unknown location. It is widely used as a landscaping specimen, especially in California in the United States of America.