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Eucalyptus michaeliana is known as the Hillgrove Gum, and grows to 30 metres tall.
The common name refers to the village of Hillgrove, east of Armidale on the Northern Tablelands of NSW. A large population of Eucalyptus michaeliana occurs near the village. The species occurs in about 3 disjunct patches – east of Armidale and Uralla and down to east of Walcha – extending towards Dorrigo (Enmore-Hillgrove-Wollomombi-areas). Then, it is found in Mount Barney National Park and nearby, north of Woodenbong in Queensland. It is then found further south in NSW, from around Wollombi to St Albans (on the northern outskirts of Sydney).
It forms part of dry sclerophyll forests on snady soils.
The bark is deciduous, smooth with white to grey blotches. Bark is shed in plates or flakes.
Eucalyptus spp. have simple and usually alternate adult leaves with juvenile leaves starting off opposite to alternate (disjunct). In this species, juvenile leaves are to 15 cm long and 6 cm wide, broadly lanceolate to lanceolate, concolorous and dull green. Adult leaves are to 20 centimetres long by 2 to 3 centimetres wide, lanceolate, leathery, dark green on both surfaces with a prominent mid-vein.
The primary inflorescence of “eucalypts” (Angophora / Corymbia / Eucalyptus) is an umbellaster (an umbel-like cluster of flowers). In the flowers of Corymbia and Eucalyptus, the petals and sepals are fused into the distinctive calyptra / operculum (bud cap) which is shed when the flower opens (in some species, 2 bud caps (opercula) are shed). The flowers are conspicuously staminate – where many stamens are basically taking over the role of the petals, all surrounding one central carpel. In this species, buds are carried in umbellasters of from 3 to 7 with the umbellasters further clustered into groups of from 3 to 5. Flowers are white and 1.5 centimetres across. Flowers are an eye-catching feature because they are carried in unusually large clusters. Some plants are reputed to have purple or scarlet blooms. Blooms attract many insects. Spring is said to be the main flowering period.
The fruit of eucalypts are a woody capsule (commonly called ‘gum nuts’) which come in a wide variety of shapes with the top part having a sunken, flat or raised disc and with the valves inserted, disc-level, exserted to strongly exserted. In this species, they are cup-shaped to barrel-shaped, to about 0.5 cm long and wide, with a level disc and with valves inserted or at rim level.
Author’s notes:
Eucalyptus michaeliana is an attractive tree and could be cultivated as a “stand-alone” specimen or incorporated in shelterbelts or windbreaks. The species is probably too large for most suburban gardens.
The specimens, in our cold climate garden (near Armidale), flower in February. Small gum nuts are barrel-shaped.
Cultivated specimens often have foliage almost to ground level. It has a history of being successfully planted, especially in landscapes and as street trees. It is hardy once established. Plant in full sun on a well-drained soil for best results.
Propagate from seed.
This species can regenerate from the seedbank after fire as well as produce epicormic shoots.
It is well-known that Eucalyptus is a large and diverse genus. Between 700 and 950 known species are reported, occurring as far north as The Philippines, as well as Indonesia, New Guinea, Timor and Australia. Only 16 species reportedly occur outside Australia. They occur in all Australian states. NSW currently has about 250 species. (See this website for some detailed information: https://apps.lucidcentral.org/euclid/text/intro/learn.htm).
Eucalyptus – from Greek, eu, “well” or “true” and calyptus, referring to the calyptra (καλύπτρo) or operculum, which is a bud cap or covering which covers the developing flowers. The calyptra is a fusion of petals and/or sepals and is shed when the flower opens, leaving a flower with many stamens (staminate) surrounding one female part (carpel).
michaeliana – named for Reverend Norman Michael (1884-1951) who had a life-long interest in Australian botany and collected the type specimen in 1937.
This species is not considered to be at risk of extinction in the wild.
NSW Flora Online (PlantNET) – Eucalyptus michaeliana profile page https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Eucalyptus~michaeliana
EUCLID – Eucalypts of Australia – Centre for Australian National Biodiversity Research – Eucalyptus michaeliana profile page https://apps.lucidcentral.org/euclid/text/entities/eucalyptus_michaeliana.htm
ACT Government – Plant Species for Urban Landscape Projects in Canberra – Eucalyptus michaeliana fact sheet https://www.cityservices.act.gov.au/__data/assets/pdf_file/0009/1502973/Eucalyptus-michaeliana.pdf