One To Watch For
  • Last updated:
  • 21 Oct 2019

Over the years weeding at Cotton Tree, I’ve noticed the weed Barleria repens and its ongoing domination of native grasses and shrubs. This is due to its scrambling thick rooting stems that form thickets.

Many are unaware of its potential to dominate and outcompete. With new outbreaks occurring over coastal areas, it’s definitely one to watch.

Barleria repens is a spreading shrub distinguished by its tubular pink/red flowers that have five lobes produced around February to April. The fruit is small and spits open when mature to release four seeds. The leaves are opposite the stem and are a dark shiny green. The younger stems can be somewhat hairy while the older stems are generally woodier.

Common names include Coral Creeper and Coral Bells. It’s a native from Kwa Zulu to tropical Africa. It is from the Acanthaceae family and threatens the natural vegetation by densely covering the understory. It is also a risk to coastal and riparian vegetation. It is closely related to the Philippine violet (Barleria cristata) which is a taller shrub with a similar shape.

Habitat

Coastal Queensland, urban bushlands and disturbed forests, threats to riparian areas, roadsides and distributed areas. Generally it will not grow more than 70cm in height.

Dispersal and Reproduction

Barleria repens reproduces by seed and vegetatively via its rooting stems. Seeds can be spread up to a few metres from the parent plant as they are propelled and released from the fruit. Other forms of dispersal include water and animals. Garden waste dumped in bushland is a common form of dispersal as stem segments and seeds spread. Mowers and slashers also contribute to this.

Flowers and Fruits

Summer to winter, it has tubular flowers with five spreading lobes. The cultivated and naturalised form in Queensland has a bright red or pinkish red flower, while the forms common in Africa are commonly purple. Fruit is small with four seeds and the capsules are club-shaped that split open.

Leaves and Stems

Leaves are glossy and dark green. Stems produce roots quickly after touching the ground. Younger stems are hairy while older stems are woodier.

Impacts

This plant can colonise into thickets in the understory stopping the movement of animals. These thickets stop natural regeneration and cause environmental damage by colonising riparian zones.

Control Methods

Hand removal has resulted in the best reduction over time. Achieved by manually removing individual stems and plants, taking care and time to ensure to leave behind as little of the root system as possible.

In cases where it is very thick and hard to hand remove completely, removing the flowers and immature fruit is still helpful as it prevents the opportunity for dispersal and reduces the risk of new infestations in surrounding areas.

The species is generally difficult to eradicate with chemical control, but starane in the past has proven to be successful with a surfactant due to its glossy leaves. Other applications that can help are also stem scraping and foliar spray.

Article provided by Ashley Goodman