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Leptospermum petraeum

Family: Myrtaceae

A spreading and stiff shrub to 3 metres tall by 1 metre wide.

It has a very limited distribution, growing around the Kanangra area in Kanangra-Boyd National Park in the Central Tablelands of NSW – west of Lake Burragorang and south-south-east of Jenolan Caves.

It grows on exposed rocky outcrop in shrubland.

The bark on older stems is thin and flaky.

Leaves are broadly elliptic, to 15 mm long by 6 mm wide, with a sharp point on the tip and aromatic, mid green and with a thick texture. Juvenile leaves can be incurved (bending up) with adult leaves recurved (bending down).

Leptospermum typically produce solitary flowers, or in small groups of 2s and 3s or more, within the leaf axils. Flowers have 5 petals and sepals and have a symmetrical rotate shape. Stamens are produced in groups of 5 which surround 1 carpel (female part). The prominent feature in Leptospermum is the hypanthium, a cup or vase-shaped receptacle that supports the flower.

In this species flowers are produced solitarily, to about 25 mm wide, white in colour with flowering period uncertain but likely late spring to summer. The flower buds are surrounded by yellow-brown bracts.

The capsules are to 8 mm in diameter, and they remain on the plant after seed is shed.

In the garden

This species is not known to be currently cultivated, likely due to its rare status and limited distribution. It may be cultivated in the future.

Most Leptospermum species make good garden plants.

Leptospermum are generally susceptible to the webbing caterpillar. Usually, the most effective control method for this pest is removing infestations by hand or, if necessary, you can systematically spray with a suitable pesticide. They are also prone to scale insects which is best treated by spraying white oil solution.

Propagation

They are easy to propagate from seed or cuttings.

Other information

Most Leptospermum species are endemic to Australia where most are found in southern areas of the country and many make desirable garden plants. Current estimates recognize about ninety species of Leptospermum along with many cultivars now existing.

The nectar from the flowers of one species (L. scoparium) is harvested by bees, yielding honey, which is marketed as Manuka honey.

Many Leptospermum species have an ability to regenerate vegetatively after fire with suckering basal growth and branch-shoots. They will also regenerate by seed.

The general common name, Teatree, derives from the practice of early Australian settlers who soaked the leaves of several species in boiling water to make a herbal tea.

Leptospermum – derived from the Greek words leptos meaning “fine” or “slender” and sperma which means “seed” referring to the thin brown seeds of the genus.
petraeum – Latin meaning “growing among rocks” or “rocky”, referring to the habitat of this species.

It is not considered to be at risk in the wild but it has a rare occurrence. It is protected in conserved and isolated habitat.

Australian National Botanic Gardens – Leptospermum profile page https://www.anbg.gov.au/leptospermum/

Wikipedia – Leptospermum petraeum profile page    https://en.wikipedia.org/wiki/Leptospermum_petraeum

NSW Flora Online (PlantNET) – Leptospermum petraeum profile page https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Leptospermum~petraeum

By Jeff Howes, edited Dan Clarke