Leptospermum obovatum

River Teatree

Family: Myrtaceae

A shrub producing dense, often pendulous foliage to about 2 metres tall by 1 metre wide.

It has a large distribution, with some disjunct records on the northern tablelands, but with most of its range extending south from the Kandos area, through Sydney and the southern tablelands and south coast, through Victoria, right to the South Australian border.

It grows in amongst granite and sandstone rocks near streams in dry sclerophyll woodland and also grows on swamp edges forming part of shrublands.

It has persistent fibrous bark on larger stems.

Leaves are obovate to oblanceolate, to 20 mm long and to 8 mm wide aromatic, mid-green to dark green in colour.

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, the flowers are borne singly, sometimes in pairs, to 12 mm wide and white in colour, occurring from November to January. There are reddish-brown bracts at the base of the flower bud.

The fruit is a capsule, to 8 mm in diameter, persisting on the plant until seeds are shed.

In the garden

This one is popular in cultivation (when all teatrees are considered). They are available from nurseries and some cultivars are in existence (see below).

It is a useful dense screening/hedge shrub for moist areas and will grow in heavy shade. It can flower profusely, making it very attractive.

Most plants have a pendulous habit. It does not grow overly large which also lends to its appeal.

It will reportedly grow in a range of soils. Provide adequate drainage but it may take periods of inundation (boggy soils). It can tolerate deep shade; however a open sunny to part-shade position will work best. Prune as required to encourage shape and density.

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

There is a cultivar available called ‘Starry Night’. It is reported to be fast growing with purple-bronze new growth and a weeping habit.

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.
obovatum – Latin – referring to the obovate leaves – best described as an upside-down egg shape where the top half of the leaf is wider than the lower, with overall leaf length generally short.

It is not considered to be at risk in the wild.

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

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

Gardening with Angus – Leptospermum ‘Starry Night’ profile page
https://www.gardeningwithangus.com.au/leptospermum-obovatum-starry-night-tea-tree/

By Jeff Howes, edited Dan Clarke