Name:
Lantana (Lantana camara)
Description
Lantana is a sprawling or scandent shrub or vine normally 1-3 m high, and on rare occassions to 6 m high in favourable conditions, often growing in dense thickets. The stems and branches are normally quadrangular in cross-section when young, often well armed with short recurved prickles and sometimes with glands or glandular hairs. The leaves are in opposite pairs on the stem, with successive pairs borne at right angles to each other. The leaves are ovate to oblong-ovate, about 4-10 cm long, 3-6 cm wide, often covered with rough coarse hairs on the upper surface and strongly aromatic due to glandular hairs. The margins are bluntly toothed. The inflorescence is a dense head of 20-40 brightly coloured flowers, ranging from yellow, orange-yellow, deep orange, deep red, pink, rose-pink to white, often with a variation of colours in each head of flowers and with the flowers having the ability to change colour as they mature. The fruit has many berries, which ripen from green to shiny purple-black and contain one or two pale seeds.
Lantana is an ‘aggregate species’, or ‘species complex’. There are several natural variants of Lantana camara across its presumed native range in the tropical Americas, and in addition some hundreds of horticultural colour and habit varieties have been developed around the world, with over 650 varietal names coined.
For further information and assistance with identification of Lantana contact the herbarium in your state or territory.
Seed longevity in the soil is not well documented, but seeds are thought to remain viable for several years under natural conditions. Work in progress suggests an in-soil longevity of at least three and up to five years. Germination rates are reported as being increased by removal of fruit pulp, as occurs with passage through the digestive system of birds and by warm temperatures, light, and high soil moisture. Germination rates even under favourable conditions are sometimes reported as fairly low (<45% or less), but as fruits may set at rates of up to several thousand /m2 there is a considerable soil seedbank.
Lantana can resprout from the base if the shoot dies, extending the life of individual plants.
Distribution:
Lantana is now found across four million hectares of land east of the Great Dividing Range, from Mount Dromedary in southern New South Wales to Cape Melville in northern Queensland. Isolated infestations exist in the Top End of the Northern Territory, around Perth in Western Australia, and on Lord Howe and Norfolk Islands. Although present Australia wide as a garden ornamental, it has not naturalised to any serious extent elsewhere.
Habit:
Shrub, Vine
Key points:
- Lantana (Lantana camara) is a thicket-forming shrub that has spread from gardens into pastures, woodlands and rainforests on the east coast.
- It typically invades disturbed land and river margins, extending its range in response to rainfall.
- It threatens agriculture and pastoral production, forestry and biodiversity of conservation areas, and may be toxic to stock.
- The highest priority for Lantana control is preventing its spread into northern Australia and west of the Great Dividing Range.
- Integrated control should combine fire, mechanical, chemical and biological methods, and revegetation.
How it spreads:
Lantana spreads in two ways. Layering is a form of vegetative reproduction where stems send roots into the soil, allowing it to quickly form very dense stands and spread short distances. Also, birds and other animals such as foxes consume and pass the seed in their droppings, potentially spreading it over quite large distances. The germination rate of fresh seed is generally low, but improves after being digested.
Butterflies, bees and other insects are attracted by the nectar and pollinate Lantana flowers. About half of the flowers produce seeds, typically 1-20 seeds on each flower head. Mature plants can produce up to 12 000 seeds every year. Seeds are thought to remain viable for several years under natural conditions.
Lantana is allelopathic and can release chemicals into the surrounding soil which prevent germination and competition from some other plant species.
Where it grows:
Lantana can grow in high-rainfall areas with tropical, subtropical and temperate climates. It does not tolerate salty or dry soils, waterlogging or low temperatures (<5 ºC). It thrives on rich, organic soils but also grows on well-drained clay and basalt soils. Sandy soils tend to dry out too rapidly for Lantana unless soil moisture is continually replenished. It has been reported at altitudes up to 1000 m in Queensland.
Lantana invades disturbed sites, especially open sunny areas, such as roadsides, cultivated pastures and fencelines. From there it can invade the edges of forests, but it does not fare as well under a heavy canopy as it is not very shade tolerant.
Flower colour:
Multi-colour
Distribution map:
Impacts:
Lantana is a Weed of National Significance. It is regarded as one of the worst weeds in Australia because of its invasiveness, potential for spread, and economic and environmental impacts. Lantana forms dense, impenetrable thickets that take over native bushland and pastures on the east coast of Australia. It competes for resources with, and reduces the productivity of, pastures and forestry plantations. It adds fuel to fires, and is toxic to stock.
Most variants of L. camara in Australia are toxic to domestic livestock (sheep, cattle) to some degree, with only three thought to be consistently non-toxic. There does not appear to be any documentation of palatability and toxicity to native fauna. Toxicity seems likely to be related to genetic factors, not environmental ones. Some toxic reactions have been recorded in humans, especially children.
Lantana dominance appears to adversely affect the species richness of soil fauna assemblages, such as ants, and decreases the diversity of soil fungi. It can also affect flora diversity by reducing seedling germination and by increasing the chance and severity of fire in plant communities such as dry rainforest. Lantana has been identified as a potential threat to many threatened and endangered plants and animals and a number of endangered ecological communities.
Origin:
Lantana occurs naturally in Mexico, the Caribbean and tropical and subtropical Central and South America. It is considered a weed in nearly 50 countries.
