Miconia

On 1 July 2017, the Noxious Weeds Act 1993 was replaced by the Biosecurity Act 2015. The Weed biosecurity section of this website is being reviewed, and information currently on this page may not reflect the new legislation.

 

Miconia seeds. Miconia leaf with the
distinctive purple underside
and three veins.
Miconia flowers. Underside of Miconia
at Bilambil.
Miconia seedling
discovered at Bilambil.

Miconia (Miconia calvescens), also known as Velvet tree, is a potentially devastating weed of Australian rainforests. All Miconia species are declared noxious throughout NSW as a class 1 weed and must be eradicated from the land and the land must be kept free of the plant.

As a notifiable weed, all outbreaks must be reported to Rous County Council.

If you find this weed in your area or see something that may be Miconia, contact Rous County Council or Industry & Investment NSW immediately.

Miconia is a rainforest tree native to South America and can be found from Mexico to Brazil. It is an attractive plant and a botanical curiosity. It has been cultivated in glasshouses in Europe since the 1850s. It is recorded as a serious weed in Hawaii and French Polynesia, including Tahiti, where it has devastated the native flora and fauna. It is naturalised to a lesser extent in Sri Lanka and Jamaica. This weed ultimately poses a threat to all tropical and subtropical rainforests.

Miconia was introduced to a botanical garden in Tahiti in 1937. It is now common in over 70% of the island and is described as the ‘green cancer’ of Tahiti. The plant has a similar history in Hawaii and is locally described as the ‘purple plague’. The introduction of Miconia into Australia as a garden ornamental was first recorded in Townsville in 1963. During the 1970s and 1980s it became a popular ornamental foliage plant and was sold by several nurseries in Queensland and NSW. Naturalised populations are known to occur in Far North Queensland, and small infestations or backyard plants have been found at Tully, Innisvale and the Cairns region. In Queensland and Tasmania, plants must be destroyed.

The climate throughout much of northern and eastern Australia is ideal for the plant, and in April 2003 sixteen Miconia plants were seized from a nursery on the Far North Coast of NSW.

In 2008 FNCW (now Rous County Council) staff, with assistance from the public, discovered a single Miconia plant growing in scrub at Tomewin. Further inspection found two seedlings, and a short distance away the parent plant was found near a house in a garden. As a result of these finds, in 2010 an intensive investigation of the area was undertaken, locating two more sites, one at Burringbar and another at North Tumbulgum. Further assistance from the public was instrumental in locating these new sites. All plants have been eradicated, but Council is alert to the possibility that they were not the only ones.

The importation of all Miconia species into Australia is prohibited under Australian quarantine regulations.

The problem

  • Miconia is an unusually aggressive invader of moist rainforest habitats.
  • This weed has the potential to cause irreversible damage to rainforests. Under favourable conditions, Miconia will form dense thickets in rainforest understoreys and can completely replace native vegetation.
  • In Tahiti, half of the endemic plants are considered to be directly endangered due to Miconia.
  • The weed has the ability to thrive in heavy shade as well as sunlight.
  • Mature Miconia trees can flower and fruit three times a year, producing up to five million seeds. Birds are the primary vectors for dispersal of Miconia seeds, but small mammals are also a major contributor.
  • Because the seeds stick to mud on shoes, clothing and machinery, humans also contribute to the spread of this noxious tree.

Identification

  • Miconia is a small tree, up to 15m tall.
  • Its leaves are 60-70cm long (up to one metre), dark green with three distinct parallel veins on the upper surface and distinctly purple-blue below. Young stems and leaves have velvety hairs.
  • Flowers are numerous, sweet scented, white to pink in colour, and very short-lived (12-24 hours after opening).
  • The dark purple fruits are about  1cm in diameter, sweet tasting, and very attractive to birds. Each fruit contains 50-200 seeds.
  • Seeds are tiny, about 0.5mm in diameter.

Propagation

Flowering and fruiting begin after four to five years, and can re-occur several times a year. Germination requirements are varied. Most seed remains dormant until stimulated by an opening in the canopy, however seed will also germinate under heavy shade. Seeds remain viable in the soil for five years or more. Miconia is also known to spread vegetatively through layering and re-sprouting.

Control

There are no herbicides currently registered in NSW for the control of Miconia. On larger trees, cut stump and frilling methods have been used successfully. In large infestations, removal of adult trees results in a massive germination from the soil seedbank. Uprooting is effective on plants less than about three metres tall.

Legislation

  • All Miconia (Miconia spp.) species are class 1 noxious weeds throughout NSW under the NSW Noxious Weeds Act 1993.
  • This weed must be eradicated from the land and the land must be kept free of the plant.
  • As a notifiable weed, all outbreaks must be reported to the local council.
  • If you have seen this plant, please report it to Rous County Council or Industry & Investment NSW for positive identification.

Distribution map as at May 2017

Predictive mapping supplied by Queensland Biosecurity