Weeds on Lord Howe Island
Over 700 introduced plants have been recorded on Lord Howe Island, mostly in private gardens. Of these, 270 have characteristics that classify them as “invasive”. Currently, 68 of the invasive species on the island have been declared “noxious”. In comparison there are 156 weeds that have been declared noxious in the whole of New South Wales. We have more than our fair share!
The Lord Howe Island Board maintains a full list of the weeds on the island – it can be downloaded here. Download the list.
Some of the weeds that the Friends regularly treat are shown below.
Solanum mauritianium
A small tree up to 4m high with large furry leaves growing in disturbed areas.
A small tree to 4m high with large furry leaves growing in disturbed areas. The Friends treat this mainly on Transit Hill and Clear Place.
Native to: South America.
Leaves: large, to 30cm, soft, furry, whitish under.
Stems: cloaked in fine whitish hairs
Flowers: bunches of small violet flowers 15 – 25 mm diam.
Fruit/seeds: bunches dull yellow berries 15mm.
Dispersal: birds.
Reproduction: seeds germinate readily.
Treatment: hand pull seedlings; larger plants cut stem and apply undiluted glyphosate.
Psidium cattleianum
A shrub or small tree up to 6 metres tall, brought to the island for its tasty fruit, but spread widely by birds.
A shrub to small tree 6 metres, brought to the island for its tasty fruit, but spread widely by birds. This has been declared the worst woody weed of subtropical islands in the world.
The Friends have worked on this weed on the foothills of Mt Lidgbird and Intermediate Hill. The LHIB have removed over one million and now only occasionally encountered in remote areas.
Native to: Brazil
Leaves: small, glossy green, ovate, somewhat leathery.
Stems: red-brown, mottled green & pink
Flowers: cream, 7mm diam, with many stamens.
Fruit/seeds: red berry 30mm diam. With 20 or more seeds; autumn.
Dispersal: birds, humans, water.
Reproduction: seeds germinate readily.
Treatment: hand pull seedlings; larger plants cut stem and apply undiluted glyphosate.
Asparagus plumosus
A perennial vine climbing up trees using sharp hooks on the stem. Mainly confined to the settlement areas.
This is a perennial vine climbing up trees using sharp hooks on the stem. Mainly confined to the settlement areas; the Friends have spent many weeks clearing this from Transit Hill and Stevens Reserve.
Native to: Southern Africa
Leaves: soft, feathery foliage.
Stems: Green, hairless, twining, with short, down-curved spines.
Flowers: 5-7mm, green-white, spring & summer.
Fruit/seeds: black berries, 5mm diam, winter.
Dispersal: birds
Reproduction: seeds germinate readily; broken rhizomes sprout.
Treatment: hand pull seedlings; large plants scrape stem for 20cm from base and apply undiluted glyphosate; cut off above scrape and apply drop of undiluted glyphosate. Bag fruit.
Asparagus aethiopicus
A sprawling, spiny herb with numerous stems spreading 2 metres from the central crown.
A sprawling, spiny herb with numerous stems spreading 2 metres from the central crown.
This was the initial focus of Friends groups from 1995, who spent more than 40 week-long weeding eco-tours removing it from Transit Hill and the Lagoon foreshore. It is still occurring in remote hill and mountain areas.
Native to: South Africa
Habitat: rainforest, dune areas, prefers light.
Leaves: small, flattened, bright green, linear leaf.
Stems: green, with small spines.
Flowers: 3-5 mm , white, numerous, summer.
Fruit/seeds: prolific red berries 5-8 mm diameter.
Dispersal: birds
Reproduction: from seeds and rhizome.
Treatment: hand pull seedlings; larger plants bag seeds and use a knife or mattock around base to sever roots and remove crown.
Anredera cordifolia
A fleshy leaved succulent climber that develops small tubers on the stems that will sprout when fallen on the soil.
A fleshy leaved succulent climber that develops small tubers on the stems that will sprout when fallen on the soil.
The Friends have removed this on leases and in Stevens Reserve.
Native to: South America.
Habitat: rainforest margins.
Leaves: fleshy, heart shaped.
Stems: brown, warty, fleshy.
Flowers: small, white in drooping clusters 10cm long.
Fruit/seeds: rarely sets seed in Australia.
Dispersal: tubers transported by water, birds.
Reproduction: from aerial & underground tubers.
Treatment: manually remove stems, roots, tubers and seedlings; bag all parts and dispose carefully. Continue follow up for months. For large plants stem scrape with 100% glyphosate.
An annual herb to one metre tall, with one white flower in summer.
The Friends treat North Beach dune vegetation each year and have removed it from there; occasionally targeting some other areas.,
Native to: Asia.
Habitat: open forest understorey, cliffs, and dunes.
Leaves: 5-15cm long, thin leaves along stem.
Stems: green, smooth.
Flowers: funnel shaped, to 15cm long; white, purple tinge.
Fruit/seeds: seed pod 8cm long, green, turning brown & releasing numerous thin, papery seeds.
Dispersal: wind
Reproduction: seeds germinate in moist areas.
Treatment: dig bulb out; or cut and paint stem with glyphosate. Pulling stem oiut can weaken the plant.
Pittopsorum undulatum
A small tree to 10 metres high, with distinctive orange fruits.
A small tree to 10 metres high, with distinctive orange fruits; the Friends encounter this one occasionally when working on Transit Hill.
Native to: Eastern Australia.
Habitat: rainforest.
Leaves: shiny, wavy margins, oily smell when crushed.
Stems: orange/brown, bark slightly tessellated.
Flowers: masses of white flowers early spring.
Fruit/seeds: round, orange fruit 14mm, splits to expose numerous sticky red seeds.
Dispersal: birds.
Reproduction: seeds germinate readily.
Treatment: seedlings pull out by hand; larger plants cut stem and apply undiluted glyphosate
A tall shrub to 3 metres with large, divided, glossy leaves.
The Friends have nearly removed this from the area known as Edie’s Glen, a gully just behind Pinetrees
Native to: Asia and Africa
Habitat: forest margins, damp areas.
Leaves: large, hairless, divided into 7-9 toothed lobes.
Stems: woody, green, hollow.
Flowers: long clusters 8 to 15cm long; male yellowish, female red, on same plant.
Fruit/seeds: soft, spiky, reddish-green capsule, 1-2 cm diam.
Dispersal: explosive fruit that disperses seeds.
Reproduction: seeds germinate readily.
Treatment: hand pull seedlings; mature plants cut stem and apply undiluted glyphosate.
Physalis peruviana
A small spreading shrub probably brought over because of its edible fruits.
A small spreading shrub probably brought over because of its edible fruits.
This grows in disturbed areas in the settlement and beyond.
Native to: South America.
Leaves: 6cm long, hairy.
Stems: green.
Flowers: 15mm, dull yellow with brown spots.
Fruit/seeds: 40mm long papery case enclosing a single orange berry 15mm.
Dispersal: birds.
Reproduction: seeds germinate readily.
Treatment: hand dig, bag fruits.
Ageratina adenophora
An erect perennial herb to 2 metres tall, growing in dense clumps in disturbed moist, sunny areas.
An erect perennial herb to 2 metres tall, growing in dense clumps in disturbed moist, sunny areas.
The Friends groups hand remove this from areas being worked. It is in remote mountain areas and requires research into biological controls.
Native to: Central America.
Leaves: soft, triangular, toothed.
Stems: brittle, reddish brown with a distinctive smell.
Flowers: very small white flowers in floral head 6mm diam. In Spring.
Fruit/seeds: tiny seeds late spring/summer.
Dispersal: wind and water.
Reproduction: germinates readily from seed.
Treatment: hand dig; spray glyphosate 1:100 plus LI700 surfactant 5ml/L.
Euphorbia paralias
A herb to 70cm tall, arrived by seeds floating in the ocean currents in the 1990s, and is on our western beach dune margins.
WARNING: Broken stems ooze a toxic milky sap that may irritate the skin or eyes.
A herb to 70cm tall, arrived by seeds floating in the ocean currents in the 1990s, and is on our western beach dune margins. The species is widely naturalised on Australia’s southern coasts. The Friends began removing this in 2004, and some locals also regularly walk the beaches to remove it.
Native to: Europe, northern Africa and western Asia
Leaves: fleshy blue/green, 20mm long, crowded together along the stem
Stems: multiple, thin stems
Flowers: Small yellow/green flowers at the end of the stems, from September to May.
Fruit: green capsules 5 mm diameter. Seeds grey 3mm diameter.
Dispersal: seeds floating on ocean currents.
Reproduction: germinates readily from seed.
Treatment: hand dig, usually quite easy as it grows in sand.
Ipomea cairica
A vigorous perennial climber that is capable of very rapid growth, spreading quickly .
A vigorous perennial climber capable of very rapid growth, spreading quickly, either forming a dense mat along the ground or climbing on any vertical support into the canopy. Infestations can smother native vegetation, reducing biodiversity and displacing native animals due to habitat destruction. The Friends have been working on this weed on North Head and other areas.
Native to: Tropical Asia and Africa
Leaves: deeply divided leaves with 5-7 lobes, up to 9 cm long and wide.
Stems: multiple, thin stems that travel tens of metres; and roots form at nodes.
Flowers: tubular, violet to purple; up to 6cm long
Fruit: a round capsule 9–11 mm diam., splitting into 4 valves; seeds hairy.
Dispersal: seeds floating on ocean currents.
Reproduction: germinates readily from seed.
Treatment: hand dig, roll stems up and hang in trees; scrape stem and apply glyphosate.
Setaria palmifolia
A tall perennial grass to 150cm high, a prolific seeder and grows in disturbed areas and clearings from tree falls.
A tall perennial grass to 150cm high, a prolific seeder and grows in disturbed areas and clearings from tree falls.
The Friends brought attention to this in the early 2000’s and it is now targeted for removal.
Native to: India and S.E. Asia.
Leaves: to 150cm long, 6 cm broad, parallel veins.
Stems: green.
Flowers: small flowers in cluster on stalk to 100cm long.
Fruit/seeds: small grass-like seeds.
Dispersal: wind, human traffic.
Reproduction: seeds germinate readily.
Treatment: hand pull or spray with glyphosate 1:100.
