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A weed is a plant in the wrong place.
In Kuranda, a variety of weeds introduced since white settlement have already caused great damage to the natural environment. Some, such as lantana, have been here a long time. Others have only been discovered recently. A big problem with weeds is that plants with the potential to become weeds can live for many generations in an environment, slowly adapting until a critical point is reached when the plant begins to spread and become a menace to other vegetation or wildlife. For this reason many plants that are not yet a real problem in the area have been included in many published lists of weeds, because they have the potential to become weeds in the future. Any introduced plant that has the ability to survive in rainforest, for example, should be considered a potential weed.
Below is a list of the 16 most significant weeds in the Kuranda area, compiled by members of Kuranda Envirocare. Descriptions and photographs of these weeds follow.
An excellent illustrated spiral bound book of weeds in the Wet Tropics is available, from Kuranda Envirocare, for sale at around $5 per copy. The book is titled “Weed Pocket Guide, Agricultural and Environmental Weeds, Far North Queensland“, and was compiled by the Wet Tropics Management Authority, in conjunction with the FNQLG Pest Plan Advisory Committee and the DNRM. Weed eradication sheets giving advice on how to get rid of certain weeds are also available.
It can be difficult to positively identify weeds, even with the help of photographs. If in doubt, it is likely that someone from Kuranda Envirocare can assist you in your identification, and with control and eradication advice.
Weed control sheets generally offer advice on chemical control of weeds. Herbicides allow quick and often efficient treatment of large areas of weeds, but they have a number of disadvantages. Some kill plants other than the weeds they are targeting, leaving bare areas that may well grow another crop of weeds. Some have serious impacts on animal life, such as frogs or fish. Many are poisonous to people, and should only be applied with caution, after reading the information that comes with them. Always wear protective clothing and avoid spilling chemicals on exposed skin. Some are also expensive or only obtainable in large quantities.
For these reasons many people prefer to avoid chemical treatments if possible. There are a number of alternative ways of removing weeds listed below.
Physical Removal. Weeds may be pulled by hand or dug out with a variety of tools or machinery. Some weeds, such as Singapore Daisy, may be spread by such methods, so precautions must be taken. If the plants are placed in black plastic bags and left in the sun for several days, the weeds inside will no longer grow. It is best to remove weeds before seed has set.
Cutting off light. Black plastic can be spread on weeds and held down with weights. This will eventually kill the weeds, along with all other plants underneath. Some people mulch with cardboard or newspaper, which eventually decomposes, or use thick plant mulch.
Competition.While most weeds are very competitive, it may be possible to grow plants that will eventually outcompete them. If trees are planted over Singapore Daisy, for example, and maintained for several years, they will eventually take over from this invasive weed. This is the best long term solution to weed control.
These are weeds that have been found near Kuranda and are important threats to the environment. Please report them at once to Mareeba Shire Council (Ph 40 303900 - Weed Control Officer - Sid Clayton) or contact DNRM in Cairns.
Miconia (Miconia calvescens)
A shade tolerant shrub or small tree, with very large (up to 700mm) three veined leaves, often with purple undersides. This weed has taken over large areas of Hawaii and Tahiti. It is a declared plant in Queensland, and has been found in Kuranda. The small berries are spread by birds. If you see it, report it. Considerable effort has gone into eradicating this plant in Kuranda, and it is likely only a few specimens remain, able to undo all the good work so far if not removed. |
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Pond Apple (Annona glabra)
A shrub or small tree found in water courses and wet areas. The trunks often have a buttress like base, with a thin grey bark. Leaves may turn yellow in the dry season. The green, apple shaped fruits contain many pumpkin like seeds. Pond Apple forms dense thickets that replace native plants, and has been found in Kuranda along Jumrun Creek. If you see it, report it. A major eradication campaign has been very successful in removing this weed, but even one survivor can restart the infestation. |
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Brilliantaisia (Brilliantaisia lamium)
A small shrub up to 2 metres in height, with square cross-section hairy stems, purple or white pea like flowers, and heart shaped leaves. It grows in moist sunny or shady areas, and grows from seeds that develop in long cigar-shaped pods, as well as from plant fragments. This weed has been found near Kuranda, and should be immediately reported if seen. |
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Mikania Vine (Mikania micrantha)
Also known as 'Mile a Minute', this vine has heart shaped leaves in opposite pairs along the branching stems, and clusters of small greenish-white flowers. It will smother native vegetation in wet areas,in full sun or semi shade. The fine, fluffy seeds are produced in their millions, and can be carried by wind, water, machinery and animals. It has been found near Kuranda, and is a declared plant in Queensland. If you see it, report it at once. |
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Singapore Daisy (Sphagniticola trilobata)
A common sight around Kuranda, this yellow flowered scrambling daisy was introduced as a ground cover and now smothers native vegetation, even small trees. It grows in open areas along roads and waterways, and spreads by rooting from leaf nodes. Control by shading it out with mulch, trees, or black plastic; or apply herbicide (not Round Up) as per the control sheet. This is a listed undesirable plant. |
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Red Passion Flower (Passiflora coccinea)
A vigorous vine with attractive red flowers. This is now becoming very invasive around Kuranda, and has the potential to become a significant weed. Control by digging out plants or as per a weed control sheet. Listed as an undesirable plant. |
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Thunbergia (Thunbergia grandiflora)
Identifiable by the sky blue (sometimes white) flowers, this vine will grow over the largest trees, eventually smothering them. It is mostly spread by its tubers, but does seed. Contact the Weed Control Officer at Mareeba Shire Council or DNRM in Cairns, or use herbicide as per the control sheet. |
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Golden Dewdrops (Duranta erecta/repens)
This shrub has purplish blue flowers and many golden berries, that can be spread by birds. Newer varieties such as 'Sheena's Gold' are reported to be safe to use. Dig out plants, or control as per the weed control sheet. This plant is appearing in rainforest areas near Kuranda. |
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Allamanda (Allamanda spp.)
These ornamental vines have yellow or purple flowers, with whorls of simple leaves surrounding stems that ooze white sap if broken. They climb over and smother native vegetation. They can be removed by digging them out. |
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Lantana (Lantana camara)
This scrambling, heavy branched shrub can grow up to 4 metres high, with four angled or rounded stems covered in prickles. The attractive flowers are pink, yellow, orange or red, and the fruit are small and black. It is toxic to stock, and is a Weed of National Significance. It can smother native vegetation, and also causes fires to burn hotter. For herbicide use, see control sheets. It can be dug out, taking care to remove all larger roots. |
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Guava (Psidium guajava)
This small tree was introduced for its edible fruit, but forms dense thickets in disturbed rainforest areas. The fruit is full of yellowish seeds which are spread by birds and flying foxes, and also harbours fruit fly. Trees can be dug out, but they will sucker from any roots that are left. See the NRM website. |
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Sensitive Weed (Mimosa pudica)
A low, sprawling plant with pink pom-pom flowers and sharp, curved prickles, common in grassy areas around Kuranda. The leaves are touch sensitive, folding away from contact, and exposing the thorns which can inflict cuts in human skin. The thorns make mechanical removal difficult, and there will be residual seed germinate in following years. For chemical control, check the control sheet. |
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African Tulip (Spathodea campanulata)
This grows into a large tree, with large, bright orange, pea-shaped flowers, and pinnate leaves. The bark is light coloured and rough, and the timber is soft and light. Introduced as an ornamental, it has shown that it can colonise disturbed rainforest and river systems. It is difficult to remove mechanically since it can sucker from its root system. For chemical control, see the control sheet. |
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Syngonium (Syngonium podophyllum)
This common indoor plant forms a vine with large lobed leaves, often found growing up tree trunks. It can climb over and smother native vegetation. The plants can be dug out, or advice on chemical control obtained from Weed Control Officers in Mareeba Shire Council or DNRM, Cairns. |
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Zebrina (Tradescantia zebrina)
This is a groundcover similar to ‘Wandering Jew’ or ‘Creeping Jesus’, with purplish leaves and blue/purple flowers. It is invasive and displaces native ground cover species. It grows from nodes in contact with the ground. Remove mechanically, taking care not to spread the weed. Storage in sealed black plastic bags in the sun for a week should kill the plants inside. |
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Leucaena (Leucaena leucocephala)
This shrub or small tree can grow to several metres in height, and is able to grow in drier parts of the Kuranda area. The foliage is feathery, like some wattles, and the ‘ball’ flower is also similar to a wattle, but cream and up to 12 mm across. The flat green pods grow in clusters and turn brown when ripe, when they shattter, spreading the seeds that can then be carried away by water or on machinery. Introduced as a fodder plant, this tree can form dense stands. Get control advice from weed control officers, or grub out individual trees. |
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