Lantana camara L. (SHRUB VERBENA)

Lantana camara L.

BOTANICAL NAMES: Lantana camara L.

FAMILY: Verbenaceae

SYNONYMOUS NAMES : Lantana aculeata , Lantana tiliifolia, Camara vulgaris, Lantana scabrida

COMMON NAMES: big sage, wild sage, red sage, white sage, tickberry, Yellow sage, shrub verbena, Common lantana,

GENERAL DESCRIPTION: Lantana camara is a significant weed of which there are some 650 varieties in over 60 countries. It is established and expanding in many regions of the world, often as a result of clearing of forest for timber or agriculture. It impacts severely on agriculture as well as on natural ecosystems. The plants can grow individually in clumps or as dense thickets, crowding out more desirable species. In disturbed native forests it can become the dominant understorey species, disrupting succession and decreasing biodiversity. At some sites, infestations have been so persistent that they have completely stalled the regeneration of rainforest for three decades. Its allelopathic qualities can reduce vigour of nearby plant species and reduce productivity in orchards. Lantana camara has been the focus of biological control attempts for a century, yet still poses major problems in many regions.

FEATURES:Lantana is extremely easy to grow requiring little attention and is seldom bothered by pests or disease. It has low water requirements and can be used in xeriscapes and can handle the heat growing in containers and hanging baskets under sunny conditions. Lantana is a favorite species for butterflies and non-invasive lantanas should be a part of any butterfly garden.
Another lantana species that is also a popular garden plant is the weeping or trailing lantana Lantana montevidensis which is low growing trailing species that is particularly nice for hanging containers and groundcover.

DISTRIBUTION: Naturalized in approximately 60 countries or island groups between 35 N and 35 S latitudes. Occurs widely in the Asia-Pacific region, Australia, New Zealand, Central and South America, West Indies and Africa. The plant is still widening its range.

HABITAT: The diverse and broad geographic distribution of lantana is a reflection of its wide ecological tolerance. It occurs in diverse habitats and on a variety of soil types. Lantana generally grows best in open, un-shaded conditions such as wastelands, the edges of rain forests, on beachfronts, in agricultural areas, grasslands, riparian zones, scrub/shrub lands, urban areas, wetlands and forests recovering from fire or logging. Roadsides, railway tracks and canal banks are favored by the species. It doesn't grow at ambient o temperatures below 5 C. The plant is found at altitudes from sea level to 2,000 m and can thrive very well under rainfall ranging from 750 to 5000 mm per annum. Lantana does not invade intact rain forests, but is found on their margins. Where natural forests have been disturbed through logging creating gaps, Lantana encroaches in the gaps. Further logging aggravates the condition and allows lantana to spread or become thicker in its growth. It cannot survive under dense, intact canopies of taller native forest species. The plant is susceptible to frosts and low temperatures, saline soils, boggy or hydromorphic soils, low rainfall, coralline soils with poor water-holding capacities and high incidence of tropical hurricanes.

BIOLOGY:Lantana camara is a low, erect or subscandent, vigorous shrub which can grow to 2 - 4 meters in height.

The leaf is ovate or ovate oblong, 2 - 10 cm long and 2 - 6 cm wide, arranged in opposite pairs. Leaves are bright green, rough, finely hairy, with serrate margins and emit a pungent odour when crushed.

The stem in cultivated varieties is often non- thorny and in weedy varieties with recurved prickles. It is woody, square in cross section, hairy when young, cylindrical and up to 15 cm thick as it grows older. Lantana is able to climb to 15 m with the support of other vegetation.

Flower heads contain 20 - 40 flowers, usually 2.5 cm across; the
colour varies from white, cream or yellow to orange pink, purple and red. Flowering occurs between August and March, or all year round if adequate moisture and light are available.

Pollinators include lepidopteran species and thrips.

The fruit is a greenish blue-black colour, 5 - 7 mm in diameter, drupaceous, shining, with two nutlets; seed setting takes place between September to May with 1 - 20 seeds on each flower head.
Mature plants produce up to 12,000 seeds annually. Seed germination occurs when sufficient moisture is present; germination is reduced by low light conditions.

The root system is very strong with a main taproot and a mat of many shallow side roots.

Fruit dispersal is through frugivorous birds, fox and rodents. Germination rate of fresh seed is generally low, but the germinability gets improved when the seed passes through the digestive system of birds and animals. High light intensity and soil temperature will stimulate germination of seeds which means that clearing of forest areas, inappropriate burning and other disturbances will help spread of the weed. Seeds are capable of surviving the hottest fires.

USES: 

In warm winter zones use lantana and its cultivars in mixed beds and borders. Lantana will add vibrant long-lasting color to shrub groupings. This is a fast growing shrub that is quick to flower so gardeners in cold climates can enjoy this tropical plant as an annual. Lantana tolerates salt spray and can be used in beach plantings. Lantana makes an excellent container plant and several smaller sized cultivars are offered just for this use.
There are more than a 100 Lantana species and many of these are showing up in garden centers in one form or another. If you live in Zone 8-12 look for lantana varieties and hybrids at your garden center that are better behaved than the species - avoid digging naturalized lantana from the wild for your garden to avoid furthering its spread. Choose selected garden varieties instead.

Medicinal:---- Studies conducted in India have found that Lantana leaves can display antimicrobial, fungicidal and insecticidal properties. L. camara has also been used in traditional herbal medicines for treating a variety of ailments, including cancer, skin itches, leprosey, rabies, chicken pox, measles, asthma and ulcers.

There are also some scientific studies which have shown beneficial effects of L .camara, such as one by R. Satish which found that an extract from the plant reduced ulcer development in rats. Extracts from the plant have also been used to treat respiratory infections in Brazil.

Ornamental:-------- L. camara has been grown specifically for use as an ornamental plant since Dutch explorers first brought it to Europe from the New World. Its ability to last for a relatively long time without water and that it does not have many pests or diseases which affect it have contributed to it becoming a common ornamental plant. L. camara also attracts butterflies and birds and so is frequently used in Florida's butterfly gardens.

Garden Uses:-------- Annual bedding plant. Containers. Houseplant.

INVASIVE SPECIES:L. camara is considered a weed in large areas of the Paleotropics where it has established itself. In agricultural areas or secondary forests it can become the dominant understorey shrub, crowding out other native species and reducing biodiversity. The formation of dense thickets of L. camara can significantly slow down the regeneration of forests by preventing the growth of new trees.

Although L. camara is itself quite resistant to fire, it can change fire patterns in a forest ecosystem by altering the fuel load to cause a buildup of forest fuel which increases the risk of fires spreading to the canopy. This can be particularly destructive in dry, arid areas where fire can spread quickly and lead to the loss of large areas of natural ecosystem.

L. camara reduces the productivity in pasture through the formation of dense thickets which reduce growth of crops as well as make harvesting more difficult. There are also secondary impacts, including the finding that mosquitos which transmit malaria and tsetse flies in Africa shelter within the bushes of L. camara.

There are many reasons why L. camara has been so successful as an invasive species, however the primary factors which have allowed it to establish itself are;

Wide dispersal range made possible by birds and other animals which eat the berries
(1)Less prone to being eaten by animals due to toxicity
(2)Tolerance of a wide range of environmental conditions
(3)Increase in logging and habitat modification which has been beneficial to L. camara as it prefers disturbed habitats
(4)Production of toxic chemicals which inhibit competing plant species
(5) Extremely high seed production (12,000 seeds from each plant per year)

TOXICITY:L. camara is known to be toxic to livestock such as cattle, sheep, horses, dogs and goats.[29][30] The active substances causing toxicity in grazing animals is pentacyclic triterpenoids which results in liver damage and photosensitivy. L. camara also excretes chemicals (allelopathy) which reduce the growth of surrounding plants by inhibiting germination and root elongation.

The toxicity of L. camara to humans is undetermined, with several studies suggesting that ingesting berries can be toxic to humans, such as a study by O P Sharma which states "Green unripe fruits of the plant are toxic to humans".However other studies have found evidence which suggests that ingesion of L. camara fruit poses no risk to humans and are in fact edible when ripe.

PROBLEMS:No serious insect or disease problems. Watch for whiteflies and spider mites, particularly on overwintering plants.

MANAGEMENT AND CONTROLS:Effective management of invasive L. camara in the long term will require a reduction in activities which create degraded habitats. Maintaining functioning (healthy) ecosystems is key to preventing invasive species from establishing themselves and outcompeting native fauna and flora.

Biological:-----Insects and other biocontrol agents have been implemented with varying degrees of success in an attempt to control L. camara. It was the first weed ever subjected to biological control, however none of the programmes have been successful despite 36 control agents being used across 33 regions.

The lack of success using biological control in this case is most likely due to the many hybrid forms of L. camara as well as the large genetic diversity which make it difficult for the control agents to effectively target all plants.

Mechanical:----Mechanical control of L. camara involves physically removing the plants. Physical removal can be effective but is labour-intensive and expensive, therefore removal is usually only appropriate in small areas. Another method of mechanical control is to use fire treatment followed by revegetation with native species.

Chemical:---Using herbicides to manage L. camara is very effective but also expensive (prohibiting its use in many poorer countries where L. camara is well established). The most effective way of chemically treating plant species is to first mow the area then spray the area with a herbicide (weed-killer).

GENERAL IMPACTS:Lantana is now a major weed in many regions of the Palaeotropics where it invades natural and agricultural ecosystems (Thomas and Ellison 1999). The plants can grow individually in clumps or as dense thickets, crowding out more desirable species. In disturbed native forests it can become the dominant understorey species, disrupting succession and decreasing biodiversity. As the density of lantana in forest increases species richness decreases (Fensham et al. 1994, in Day et al. 2003). Its allelopathic qualities can reduce vigour of plant species nearby and reduced productivity in orchards (Holm et al. 1991, in Day et al. 2003). At some sites, lantana infestations have been so persistent that they have completely stalled the regeneration of rainforest for three decades (Lamb 1991, in Day et al. 2003). Such is its impact that, for example, in south-east Queensland lantana was ranked as the most significant weed of non-agricultural areas (Batianoff and Butler 2002, in Day et al. 2003). Lantana competition may have caused the extinction of the shrub Linum cratericola Eliasson (Linaceae), and is a major threat to other endangered plants in the Galapagos Archipelago (Mauchamp et al. 1998, in Day et al. 2003). The replacement of native pastures by lantana is threatening the habitat of the sable antelope in Kenya (Greathead 1971b, in Day et al. 2003).
Lantana can greatly alter fire regimes in natural systems (Humphries and Stanton 1992, in Day et al. 2003). A research team from The School for Field Studies (SFS) Center for Rainforest Studies in North Queensland, Australia’s Wet Tropics, found that L. camara increases fire risk in dry rainforest by altering fuel loads. Through a suite of field and laboratory research methods, the authors concluded that L. camara is less ignitable than native rainforest species but creates a more continuous layer of ‘ladder’ fuels, which may allow fire to reach the forest canopy. They suggest that management of this species in fire susceptible ecosystems should include targeted physical removal to reduce fuel loads. (Berry et al 2011).

It can affect agriculture in a number of ways. In plantations in south-east Asia and the Pacific Island communities it can reduce productivity and interfere with harvesting. It may affect economic viability of crops such as coffee, oil palm, coconuts and cotton (Holm et al. 1977, in Thomas and Ellison 1999). In Queensland, loss of pasture is the greatest single cost of lantana invasion in grazing areas (A$3m per year at 1985 values) (Culvenor 1985, in Day et al. 2003). In dense stands of lantana, the capacity of the soil to absorb rain is lower than under good grass cover (Cilliers 1983, in Day et al. 2003). This could potentially increase the amount of run-off and the subsequent risk of soil erosion in areas infested with lantana. Lantana has been implicated in the poisoning of a number of animals including cattle, buffalo, sheep and goats (Sharma et al. 1988, in Day et al. 2003) (its leaves and seeds contain triterpenoids, which cause poisoning and photosensitivity). Poisoning mainly occurs in newly introduced young animals without access to other fodder (Everist 1974, Yadava and Verma 1978; Sharma 1994, in Day et al. 2003).

Lantana has many secondary impacts, especially in many tropical countries where it can harbour several serious pests. Malarial mosquitoes in India (Gujral and Vasudevan 1983 in Day et al. 2003) and tsetse flies in Rwanda, Tanzania, Uganda and Kenya shelter in bushes and are the cause of serious health problems (Greathead 1968, Katabazi 1983, Okoth and Kapaata 1987, Mbulamberi 1990 in Day et al. 2003).

SOURCES:>> http://en.wikipedia.org/wiki/Lantana_camara

>> http://www.floridata.com/ref/l/lant_c.cfm

>> http://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=a523

>> http://www.fao.org/forestry/13375-06ba52ce294a4e15f8264c42027052db0.pdf

>> http://www.issg.org/database/species/ecology.asp?si=56

>> http://www.daff.qld.gov.au/plants/weeds-pest-animals-ants/weeds/a-z-listing-of-weeds/photo-guide-to-weeds/lantana

>> http://www.dpi.nsw.gov.au/agriculture/pests-weeds/weeds/profiles/lantana

>> http://ntbg.org/plants/plant_details.php?plantid=6862

>>http://plants.ces.ncsu.edu/plants/all/lantana-camara/