February 20th 2013
A tasty invader?
While used in Thai cooking, a new and potentially invasive weed is emerging on Magnetic Island. Having tried the leaves your editor seriously questions the plant's tastiness but less so its weed-like character. Following is an abridged letter from Magnetic Times reader, Mr John Marlton who first spotted Piper sarmentosum at the back of his house at Osbourne Court in Nelly Bay.
Two years ago this interesting plant appeared in my garden at Nelly Bay at the base of my back fence. At the time it appeared that it was possibly the result of bird droppings. I was intrigued by the waxy leaves on long stems and mulberry type fruits with fine multiple above ground runners. Of concern to me was that within those 2 years it had spread some 30 metres or more along my back fence.
Initially I was unable to have it identified and at the time because of its vigorous growth I proceeded to apply a nasty herbicide (i.e., Round Up) to slow its spread. When I left the Island in early November 2012 there were still some live remnants of the plant in my garden.
A friend of mine, Isobel Crawford, an Associate Botanist at the Australian National Herbarium, Canberra, and an occasional visitor to the island, finally identified the plant for me as Piper sarmentosum and noted in her email to me as follows that:
"It appears to be Piper sarmentosum, in the family Piperaceae which includes the pepper which we commonly use. In 'Mabberely's Plant Book' Mabberley (2009) notes that this species is from Indomalaya and that its leaves are used in Thai cuisine. This may well explain its arrival on Magnetic Island, and probably means that we can expect that it will be recorded with increasing frequency in Australia.
At the Australian National Herbarium (CANB), we have six collections of P. sarmentosum. Only the last two (Australian collections) have been databased.
i) West Java CANB a/n 518937. 'Karru' (Sundanese) Leaves boiled and drunk for cough medicine.
ii) Purchased in St Louis Missouri from Jay International Foods. Thailand 'chapoo' used fresh to wrap 'mingkan', coconut, onion, lime, lamb, etc. Vietnam 'La Lop' as wrapper for ground beef, garlic, ginger, sesame oil, sesame seeds etc. and broiled.
iii-iv) North Borneo naturally occurring.
v) Torres Strait Thursday Island 3 Waiben Esplanade. CANB 563979. Nov. 2002. Cultivated, suckering readily. 'Apparently this vine is edible and is common on TI with stock reportedly obtained from a Thai woman. Host to insects collected by entomologist (JFG 6365). Collected as part of the Northern Australian Quarantine Strategy.'
vi) Christmas Island. CANB 9407360. April 1976. One patch in Drumsite, spreading and now covering a substantial area. Limestone. ... Leaves used for flavouring curries. Malay 'Kadok."
Isobel had also sent a copy of the above email to Betsy Jackes, who replied that " The plant is well and truly being grown around Townsville. I suspect it was introduced to foodies in Australia by Peter Murphy who died a couple of years ago. He used to run Thai cooking classes and that is where I got my plant from or cutting. Peter was at AIMS, then a consultant microbiologist working in the Pacific a lot. The gardener here at the retirement village doesn't like it forming ground cover! Initially he wanted to poison it but has since given in on it. I know it is also in Cairns because a friend there mentioned the other day to use it in salads."
Now I appreciate that some of you will already be aware of this plant, particularly those who enjoy Thai cooking. However for others, if not already of concern as a 'garden escape', particularly given the Christmas Island experience (see vi above) the plant should be cultivated with caution considering the plant's fast spreading and invasive capabilities.
Isobel has suggested that the plant be listed as an 'Environmental Weed'. If this is already being considered please let me know. Also someone who has the direct contact for the Townsville City Council's Land Protection Officer might like to send this email on to that officer.