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A small to large shrub growing to 3 metres tall by 3 metres wide.
It has a dense weeping habit and can spread more widely than it is tall. It has been in cultivation for several decades.
It is formally described as Leptospermum polygalifolium subsp. tropicum (syn: L. flavescens) which grows around the Cardwell area in northern Queensland.
Leptospermum spp. have simple and alternate leaves. In this cultivar, the leaves are narrow-elliptic / to linear elliptic, to 20 mm long by 5 mm wide, usually hairless (glabrous) and with obvious oil dots, light to mid to grey-green, often smelling like lemon when crushed.
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 culitvar, the flowers are produced solitarily, to 15 mm in diameter, white in colour, occurring from August to January. It can flower very profusely which has made it popular.
The fruit (capsules) are to 10 mm in diameter, woody, persisting after seed release.
This cultivar has been popular in the past and may be marketed under the name L. flavescens ‘Cardwell’. It is formally described as Leptospermum polygalifolium subsp. tropicum.
It is a very hardy shrub. It grows readily in a sandy, free-draining soil and will benefit from some enrichment, in full sun to part shade. It may not thrive in boggy soils. It comes from northern Queensland and so is a great plant for tropical gardens but also grows well in cooler climates.
Can be pruned to create a dense plant. Some plants will flower very heavily, creating a stunning show, so place in an area where it can be admired.
It makes a good screening plant and hedge and recommended for rockeries.
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.
Must be propagated from cuttings to maintain form and characteristics.
Most Leptospermum species are endemic to Australia where most are found in southern areas of the country and many make desirable garden plants. However, please note the following changes:
In 2023, the genus Leptospermum of about 90-100 species, was reclassified and reduced to about 34 species, occurring in south-east Asia, New Guinea, Australia and New Zealand. Australia now has at least 31 species, occurring mostly in the eastern states. NSW currently has 31 species. The remaining approximately 60 species, that were previously Leptospermum, are now classified in four new genera: Aggreflorum, Gaudium, Leptospermopsis and Apectospermum. Species in these new genera are titled as such on this website with the synonymous Leptospermum name also indicated, for clarity.
The many cultivars in existence are still titled under Leptospermum.
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 (λεπτός) meaning “thin”, “fine” or “slender” and sperma (σπέρμα) meaning “seed”, referring to the thin brown seeds of the genus.
‘Cardwell’ – named for the town of Cardwell in northern Queensland (the gateway to Hinchinbrook Island).
Australian National Botanic Gardens – Leptospermum profile page https://www.anbg.gov.au/leptospermum/
Australian National Botanic Gardens – Leptospermum polygalifolium profile page https://www.anbg.gov.au/leptospermum/leptospermum-polygal.html
Gardening with Angus – Leptospermum ‘Cardwell’ Profile Page: https://www.gardeningwithangus.com.au/leptospermum-flavescens-cardwell-tea-tree/