Weeds CRC: Enviroweeds Archive Titles

Please click on a letter to list all weeds in archive beginning with that letter.

Haematoxylum campechianum - Logwood
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I am interested in Logwood, Haematoxylum campechianum, it is a thorny tree 3 to 10 m tall, it has recently been flowering and has lots of immature fruit on at the moment.

I know there a scattering of plants at locations including Cairns, Nebo and Rockhampton, but some of these were reported some time ago.

Logwood has been collected from 3 locations around Mackay in the past, and sent to the Qld Herbarium. I have visited all of these locations and recollected from some. I have also located and collected from an additional 4 locations, with varying numbers of plants. The infestations around Mackay range from 2 to an estimated thousand logwood plants.

I located the Weed Risk assessment on Logwood on the PIER website http://www.hear.org/pier/wra/australia/hacam-wra.htm, as I find these contain useful information about dispersal methods of the species and conditions they tolerate.

A number of my observations of this species in the field give information that is not contained in this weed risk assessment including:

Shade tolerant: at one site around Mackay Logwood is growing quite well in the shade of an area of Melaleuca forest.

Dispersal: the infestations around Mackay tend to indicate that the seeds have been spread with quarry material and not intentionally (as a plant of botanical interest).

Prolific seed production: I feel this is worth further investigation for this species, I would suggest greater than 1000 seeds per square metre is not out of the question.

Tolerates mutilation: two of the trees, on a road edge, show signs of having been cut back or down at some stage and they have regrown just fine.

Is anyone aware of this species? Has anyone attempted control of this species?

I am thinking basal bark spraying or cut stump with Access and diesel are the most likely methods of control, does anyone have any other suggestions or reasons for using other control methods?

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I am familiar with this plant in its native Belize where it grows in low lying and swampy forests, often in dense groves. Giving priority to eradication from poorly drained soils might make sense.

As a valuable source of dye, it has mostly been cut out from accessible areas. Maybe there is a market for it here? Though giving the community the idea that a weed species might have value is not necessarily a good idea......

Heracleum mantegazzianum - Giant Hogweed
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INVASIVE SPECIES HEAD "UNWANTED" LIST
May 17, 2002
BioMedNet News
Bea Perks
Lax legislation, warmer weather and a blooming gardening trade are putting Britain at increased risk from alien plants, says Grant Edwards, research fellow with the Agroecology Research Group at Imperial College Wye. Plants chosen to look pretty in gardens can become choking weeds in the wild, with disastrous environmental and economic consequences. "We're not trying to get at gardeners," said Edwards, "but they have to see the problems, and how much they can do to help." (ref. 3137) Britain has been very lucky, he says, with only "a really small number of bad plants." Frequent frosts kill off most potential invaders, he adds, but climate change could remove that buffer. Awareness among British gardeners is low, says Edwards, who will be publicizing the issue in London at this year's Chelsea Flower Show, a national institution that begins on Monday. A recent "BBC Gardener of the Year" award was won for a display of one of the country's most notorious alien invaders, giant hogweed, he recalls. Giant hogweed is a "notifiable plant" in Britain. Under the 1981 Wildlife and Countryside Act, it is an offense to allow the plant to grow in the wild. Originating in the Caucasus, giant hogweed was introduced to Britain in the 19th century by gardeners impressed by its height (10 to 15 feet). It disperses seed widely, spreads quickly, clogs up waterways and produces an irritant that can cause severe blistering. Legislation in the UK is "lax" compared with that of other countries, says Edwards, a native of New Zealand. In New Zealand, the issue is recognized under the Biosecurity Act. The act includes a list of species classified as "Unwanted Organisms," says Susan Timmins, a plant ecologist for the New Zealand government's Department of Conservation (DOC). "These species cannot be sold or traded by plant nurseries, nor can they be passed around from one gardener to another," Timmins told BioMedNet News. There is no equivalent in the UK, where Edwards hopes that a voluntary code of conduct can be agreed upon. The issue is more pressing in New Zealand.
More than 10% of the country's wild flowers are recognized weeds, says Timmins, of which about three-quarters were introduced for horticulture or ornamental use. The DOC operates a National Weeds Database to monitor spread, and is about to establish a National Weed Awareness position, she adds. "We know that we can't hope to win the war against weeds without soliciting the help from the public, either to actively help us in managing weeds or simply to slow the progress of weed incursion and spread," Timmins noted.
The economic impact of plant invasion is considerable, says Dave Richardson, chief research officer at the University of Cape Town's Institute for Plant Conservation. "A huge amount has been done and is underway on this issue in South Africa," Richardson told BioMedNet News. More than 100 biological control agents have been used against 46 weed species in South Africa, and 22 species have now been brought under control. The financial losses as a result of weed growth amply justify the cost of control measures, he says. It cost $51,000 to bring the red water fern, Azolla filiculoides and a native of Australia, under control in South Africa. The plant was imported for ornamental purposes, but spreads rapidly through waterways and is estimated to have cost $58 million in lost water-resources and livestock.

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With regard to Kate's earlier posting about the Chelsea flower show, which mentioned giant hogweed, here is an article I wrote for a nursery industry magazine a couple of years ago this plant is still in the nursery trade in southeastern Australia

Giant hogweed (Heracleum mantegazzianum) readily escapes from gardens and is a rampant invader of creeks and wetlands, however that is not its biggest fault. The clear watery sap of giant hogweed contains chemicals that cause photosensitisation or photo-dermatitis. In simple terms, giant hogweed sap acts as the opposite of sunscreen. Skin contact followed by exposure to sunlight produces blisters and a painful red rash that may develop into purplish or blackened scars.

Humans are usually exposed to the sap when hand weeding or using a whipper snipper or brush cutter on the plants. There is anecdotal evidence from overseas that children have been affected when using the hollow flower stems as pea-shooters or telescopes. It is apparently toxic to dogs and horses.

Giant hogweed is native to the Caucasus Mountains and Eurasia. It became popular as a garden plant in Victorian England, and has been cultivated throughout Europe and North America. It's scientific name refers to its 'Herculean' size as it can reach 3 to 4 metres in height. A member of the Apiaceae, its flower is a typical umbel which may be 60 cm or more in diameter.

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We don't want this one here! I saw Giant Hogweed in Seatle, Washington State when I met with gov weedos in 2000. It loves high rainfall, vacant land and steep slopes. This little gem would be right at home in the Dandenongs, Blue Mountains, and maybe the hills in southern SA.
I think you will be ok in WA sandy as it does not seem to favour desert and sand dunes or great nightlife. Do you have anything else over there?????

Hieracium aurantiacum - Orange Hawkweed
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A recent visit to the Falls Creek resort with La Trobe University highlighted the problem of this potential new threat to the alpine high country, following a seemingly innocent planting in a residential garden at Falls Creek. Orange Hawkweed originated in Europe and belongs to the Asteraceae family. It looks a bit like a dandelion but has a bright orange flower and hairy stems and leaves. It spreads by runners or seed =96 with one plant producing up to 40,000 seeds per year. Currently the plant appears to be invading a few disturbed areas around Falls Creek, and has also been recorded in adjacent pockets of native vegetation. Once established, Orange Hawkweed grows to blanket the landscape and smother native vegetation. Orange Hawkweed has proven to be an extremely invasive weed overseas, notably in New Zealand. But despite being prohibited in Australia, the plant still managed to be introduced into a residential garden in the Falls Creek resort area. From there it has spread throughout the resort and recent reports suggest it may have also been transported by machinery to Mt Buller. This new weed is a potentially serious threat to the Alpine National Park, which is home to a number of threatened plant species and ecological communities, including the Alpine Bog Community and Alpine Snowpatch Community. The Alpine Bog Community in particular is already under threat in some areas from invasion by Juncus effusus and Juncus articularis. Over time, as weeds such as these are becoming acclimatised to the conditions in the Alps, they become an increasingly significant threat. It is expected that more investigations will be carried out in future to determine the likely long-term effect of these weed invasions as well as Orange Hawkweed. What will be the effect of the fires on the alpine environment? Only time will tell, but it is considered likely that the disturbance created by this seasons alpine fires could provide the perfect opportunity for Orange Hawkweed to take off and get well established within and beyond Falls Creek and into the Alpine National Park.
What can you do if you find one? Contact Falls Creek Resort Management on 5758 3224 or 0407 581 237, and advise on the location, number of plants and stage of flowering. Do not attempt to remove as disturbance can lead to further spreading of the plant. Keep an eye out for more on Orange Hawkweed, including photos, on the VNPA website www.vnpa.org.au. For more information contact Julie Kirkwood, TSN, 93416507.

Hydrcotyl bonariensis - Pennywort
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From: Tom Kennedy
Sent: Monday, 15 October 2007

Can anyone advise on treating Hydrocotyle bonariensis in a bush regen situation with or without intermingled native species?

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From: Marita Macrae
Sent: Tuesday, 16 October 2007

One way is to dab each leaf with a tiny drop of undiluted glyphosate - very fiddly - but it works.

Another is to try the Tongs of Death. Get kitchen tongs with flat blades, (not scalloped), glue a rectangle of kitchen sponge onto inside of each blade - woodglue works.Put some 1:100 solution of glyphosate (equivalent to spraying) into a can wide enough to take tongs and deep enough to hold enough solution to immerse sponges. Gently seize each leaf with tongs and wipe on solution. You could experiment to see if infestation died if you only treat every second or third leaf.

If you put the smaller tin inside a larger can it may reduce risk of small can tipping over.

Hydrocleys nymphoides - Water poppy
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Date: Wed, 12 Jul 2006
From: <cecilia@melbpc.org.au>

Last summer I was given what was purported to be a 'small waterlily' to plant in my dam/pond.

Although planted in a pot, topped with stones and sunk close to one bank, the plant swiftly escaped and in one season has taken over almost the total surface.

I have taken photos and they can be seen at

http://www.duckpond-design.com.au/theduckpond/frogpond04.htm

I have no idea how to eradicate this weed as the pond is clay based and quite deep (chest high) in one part. Doing anything in the pond wearing waders is quite frightening as the clay acts like quicksand.

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Date: Wed, 12 Jul 2006
From: Greg Brown <g.brown@caloundra.qld.gov.au>

What you've got is Water Poppy (Hydrocleys nymphoides). Bad, evil thing. Very invasive, hard to kill.

Do the best you can - dig it out if possible - using machinery if necessary. Or else cover the area with a big sheet of thick black plastic and leave on for a few months.

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Date: Thu, 13 Jul 2006
From: "Dave Burrows" <bmo@noosa.qld.gov.au>

The plant in the photo looks like [I reckon it is], Hydrocleys nymphoides, or Water poppy.

It is in Geoff Sanity's book...Waterplants in Aust. I have had one occurrence of this guy in Noosa, and it was a real bully...took over the entire dam. Now, the next question...how to get rid of it. Physical removal , or Herbicide ...not my preferred option. 24d has been used in the past.

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Date: Sat, 15 Jul 2006
From: Michael Neighbour <michael@australianecosystems.com.au>

If you can drain the pond and isolate any fauna likely to disturb weed control activities this plant could be treated with herbicide. I'd recommend a number of treatments and replacing it with a more suitable indigenous species adopted to the ponds conditions.

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Date: Mon, 17 Jul 2006
From: <cecilia@melbpc.org.au>

I am grateful to all those who identified the invasive water poppy weed which has taken over my pond.

I gather that the three basic choices to get rid of it are:
1. Cover with black plastic and leave on for several months - probably best to do in the summer.
2. Drain pond and remove mechanically - again probably best to do in the summer.
3. Eradicate with a herbicide - probably the best and quickest option.

Supposing I go with the herbicide choice (not that I like using poison, but I have to destroy this plant as quickly as I can).
1. What time of year would be best to do this?
2. Would I need to drain the pond first?
3. Will the herbicide kill all the good bugs in the pond too?
4. I have a group of allocasuarinas whose roots grow into the pond. Will they be affected by a herbicide?

Hylocereus undatus - Moonlight cactus
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From: McFadyen Rachel
Sent: Thursday, 24 April 2008

For about 20 years from 1976, our house in Kenmore/Fig Tree Pocket in Brisbane's western suburbs had a large plant of Hylocereus undatus growing up and over a tree. This plant flowered profusely during the summer months after rain, but there were few or no fruit, and fruit were never or seldom seen on other plants in the area (see Hosking, McFadyen & Auld 1988. Plant Protection Quarterly 3, 115-123.) The pest cacti Harrisia martinii however did produce lots of fruit, both in north Qld and in the Gatton and Goondiwindi areas in the south. Both kinds flower at night, with the large white flowers opening at dusk and closing again at or soon after dawn, therefore the pollinators must be night-flying insects (or possibly bats?).

At that time (30 years ago), I found it curious that H. undatus didn't produce fruit but the Harrisia cacti did, but, as the flowers of H. undatus are significantly larger with deeper 'throats', I assumed that the moths that pollinated Harrisia were not big enough to pollinate H. undatus, and that there was no moth big enough to pollinate them in Australia. I also assumed (with no evidence) that native pollinator in South America where the cacti originate was likely to be one of the really big hawk moths which occur there.

Over the years, there has been a bit more fruit visible, but the plant was largely removed and dry summers have also intervened. This year I have noticed several large plants in Kenmore/ Fig Tree Pocket (eg one on banks of the Western Freeway) which are loaded with red fruit. So what has changed? Is there a large night-flying moth now present in Queensland which wasn't here 20 yrs ago? Or is it that these cacti are not self-fertile and needed another plant in the area? - remember that all the plants in the one suburb are quite likely all one clone as people take a piece from a garden to plant in their garden. Does anyone know anything about self-compatability in these cacti?

And, finally, now that fruit are being produced, has anyone seen any evidence of seedling plants coming up? If so, these cacti may become invasive, which at present they are not - they naturalize all right but don't disperse except very slowly by water perhaps and humans moving them.

I'd be interested to know if anyone else has noticed this fruiting and has anything to explain it.

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From: Lloyd, Sandy
Sent: Thursday, 24 April 2008

pics here for those who are not sure what it looks like:
http://www.hear.org/starr/hiplants/images/thumbnails/html/hylocereus_undatus.htm

I have seen the fruit in super markets
http://www.nt.gov.au/dpifm/Content/File/p/Fruit/778.pdf
http://www.daleysfruit.com.au/fruit%20pages/Pitaya.htm

this page says the seed is 'very viable'
http://www.beautanicals.com.au/New%20Folder/Dragon%20Fruit.html

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From: Robin St John-Sweeting
Sent: Monday, 28 April 2008

In relation to Hylocereus undatus (Pitaya or Dragon Fruit Cactus) there is an interesting article in the Journal of arid environments Vol 68,Issue 1, January 2007, Pages 1-8, Valiente-Banuet et al. The article covers the pollination biology of Hylocereus undatus in the Tehucan Valley of Mexico. Valienta-Banuet outlines the study site climate as arid or semi arid with an annual rainfalll of 380 mm and an annual mean temperature of 21 degrees C. This may associate the link in pollination with the Queensland dry summer event. Valienta also refers to pollination by two night nector feeding bats and curiously bees in the day. The study found pollination was possible by both cross and self pollination.

Hyparrhenia hirta - Coolatai grass
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Date: Sun, 29 Jan 2006
From: Rachel Burchett <rachburch@yahoo.com>

I read an article in my local rag last week that I thought might be of interest regarding control of Coolatai grass (Hyparrhenia hirta) in a nearby recreation park. Apparently, mowing the area is impractical and poisoning has been tried in the past with little success. The council, with the assistance of the local fire service, are now planning to use controlled burns to stop the spread of the weed. I think the main reason this is being considered is due to the fire risk to neighbouring residents rather than the weed factor.

What really caught my eye about the article was the comments made by Liberal candidate Stephen Ernst who "criticised Salisbury Council for not addressing the problem before the fire danger season was declared on December 1." He said "Why has it taken two months into the fire season for them to recognise an issue which has been blindingly obvious? Its just good luck we didn't have a fire up there." (Leader Messenger, Jan 25)

I think this highlights the need for politicians, people in power, and those who assess/distribute funding to be educated about the issue of weed control. This politician obviously had no idea what he was talking about, and was trying to turn the perceived inactivity of the council, and the danger that the residents are now in due to a heightened fire risk, into political ammunition. I bet he felt rather silly when the council explained to him that they couldn't do the burns any earlier as the grass was still green.

Hypericum perforatum - St John's wort
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Date: Thu, 14 Sep 2006
From: Kelly Scott <kelly.scott@adelaide.edu.au>

Can anyone assist Eamon with the query below? If so, please copy your reply to <e.watson@vla.defra.gsi.gov.uk> as Eamon is not on the Enviroweeds list.

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I am investigating an interesting case of ataxia and recumency in young pheasants (some of which recover over a 24-48 period). Last month I visited the rearing site which had a predominant growth of st johns wort (which had just finished flowering). We have ruled out viral and other infectious causes of disease (and histopathology not typical of pheasant ataxia) and I am pursuing a possible "toxic" cause. Your factsheet was brought to my attention and I wonder if you have any other information specifically relating to poultry/gamebirds and exposure to sjw.

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Date: Thu, 14 Sep 2006
From: "Lloyd, Sandy" <slloyd@agric.wa.gov.au>

http://www.poultryhelp.com/toxicplants.html
On this website about plants toxic to poultry it says:

ST. JOHNSWORT (Hypericum perforatum); entire plant causes photosensitization and contact dermatitis.

Kelly, I will follow up with our veterinary toxicologist.

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Date: Thu, 14 Sep 2006
From: <glacock@doc.govt.nz>

A couple of South African fact sheets/books refer to a red fluorescent pigment called hypericin that is poisonous to stock - 1% in their diet can cause an irritation to the mouth and throat, and acute sensitivity to sunlight on exposed and unpigmented parts of the body (itchy and reddened skin). Stock losses are generally due to loss in condition and not toxicity.

Nothing on poultry and gamebirds though.


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