SOUTH AFRICA'S UNWELCOME GUEST: THE INVASIVE MELALEUCA LINEARIS
Melaleuca linearis (Narrow-leaf bottlebrush), native to New South
Wales and Queensland in Australia is a small to medium sized shrub
that grows to a height of 3m. It has flat, narrow, linear leaves that
are approximately 40 to 100 mm long. Melaleuca linearis produces
red flowers arranged in spikes on the ends of the branches, which
continue to grow after flowering and on the sides of the branches.
Flowers are seen during the Spring, from September to December in
South Africa.
The species was most likely introduced to South Africa as an
ornamental plant. Melaleuca linearis is reported as invasive in India
and has naturalised in New Zealand. It occurs in China, North and
South America, Tanzania and Uganda and has also been reported to
occur in Colombia. It grows in damp areas and is widespread along
the coasts. Species considered as naturalised have reproduced
consistently and sustained populations without direct human
intervention over more than one lifecycle.
Melaleuca linearis first discovered in South Africa in 1999. There
are currently six known naturalised populations of this species in
the country. These are found in Grahamstown (Eastern Cape), Rooi-
Els, Wolseley, Stanford, Greyton, Bot-river and Kleinmond in the
Western Cape Province. The establishment of dense M. linearis
stands can reduce existing vegetation cover and disrupt native
soils, leading to increased erosion and soil compaction. Melaleuca
linearis is highly flammable and increases the risk of wildfires. This
further endangers native wildlife and disrupts vegetation
composition.
Since its discovery, the South African National Biodiversity Institute
(SANBI) has been actively monitoring the Melaleuca linearis
populations in South Africa, and is working with other major
stakeholders to come up with a suitable management and mitigation
plan. Melaleuca linearis is currently listed as a ‘SUSPECT’ species on
the Western cape SANBI’s Directorate on Biodiversity Evidence(DBE)
invasive alien species list. Species listed as "Suspect", are species
on SANBI’s DBE radar and monitored for their potential to become
problematic invaders in the near future. Please help by reporting
sightings of this species by contact the Western Cape's DBE team
at invasivespecies@sanbi.org.za or download the iNaturalist app for
expert opinion and guidance.
