Red Alert: Poison Pea (Swainsona), National Botanic Gardens, Canberra

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Comments (11)

EcologistGreg on January 16, 2008

Ian, this is a Swainsona, but not the 'Sturt desert pea' (S. formosa) that could be confused by using that name. It appears more like S. galegifolia or S. queenslandica in form, but is unlikely to be either of these (but it could be S. g. after a recent photo I saw). The genus is typically known as poison peas.

Cheers, Greg

Ian Stehbens on January 16, 2008

Thank you Greg. I realize that you have a remarkable knowledge of Australian botany as well as geology and geography and I have enjoyed your uploads and thoroughness. Thank you also for the further information and corrections tonight - they are very much appreciated. Ian

Amelia Royan on December 1, 2008

A beautiful, if poisonous, pea. I love the colour of this Ian. Which part is poisonous? I assume the seeds. Mvh. Amelia

Orkology vegetation … on December 1, 2008

Hi Amelia. The poison peas article may explain it a bit. Generally, the poisoning occurs when stock have nothing else to feed upon and eat the plants. In normal paddock densities the scattered plants aren't an issue, and it seems to be more of a problem when the stocking management is inappropriate (too dense or without allowing the pasture to rest and recover).

Cheers, Greg.

Amelia Royan on December 1, 2008

Hello Greg. Thank you for adding all the extra info re: Swainsona. In the UK we have Senecio jacobaea, which is poisonous to livestock; but it is a very ordinary looking member of the Compositae family, so one doesn't mind digging it up. This plant is very beautiful, and so one might be tempted to leave it in a paddock. Best regards, Amelia

Ian Stehbens on December 1, 2008

Your love of colour has opened up a new world of learning, Amelia. While Greg is an authority on Australian botany and geology, you are well educated in the field also by the sounds of it.

I am pleased that we can have this level of communication on Panoramio too.

My next question is did/do kangaroos graze on poison pea, and if so did they become addicted to it and die from it too?

Warm regards to you both.


Ian Stehbens on December 1, 2008

Dear Amelia and Greg,

I thought I would take our conversation a little further by beginning to answer my own question. There is a general belief in the interior rangelands that roos are susceptible to Swainsona poisoning, but I cannot verify that though I have provided here a link to one article that alludes to that possibility. It raises some interesting possibilities in my mind, for if it is addictive for grazing animals is that the case for roos? Rain, alluvial sands, recovery of animal populations, auto-abortion in roos, low natural fertility rates of roos and coincident habitats of Swainsona and kangaroo, all in a systemic mix... would be interesting to know how they relate.

Amelia, you may also be attracted to another species of Swainsona, S. formosa, which is a very attractive desert plant, and is a protected species in South Australia, where it was chosen as the floral emblem of the State. There even the collection of seeds is regulated. You will find some attractive photos and interesting information about this beautiful flower on the linked site.



EcologistGreg on December 1, 2008

Hi Ian and Amelia

Thanks Ian, that's some further interesting info. However, I still wonder if Swainsona is being blamed for something caused by another pathogen because at the point it gets the blame it is the most prominent thing in the paddock. In this area we got 129 records of a Swainsona in 393 sites in one vegetation survey. By all accounts, that's a lot of records for the species, yet toxicity caused by 'poison pea' seems to be rare if not unheard of among the farmers with whom I work on the western slopes (lots of anecdotal comments, but none actually affected by it). As I mentioned above, I think it is once there is nothing else on which to feed that these plants are sought by stock as fodder, as they certainly have an unpleasant smell once the foliage is crushed and I don't think are favoured up until that point. I would like to see some 'guaranteed' blame on swainsona before I think it to be the cause of toxic response.

Amelia, there are other legumes that are toxic too, so it is not something particular to Swainsona. Even the garden sweet pea is toxic.

Also, in addition to Ian's comment about S. formosa, I would think if you can get seed of S. galegifolia (also here), S. queenslandica, S. monticola, S. behriana or S. reticulata they would probably grow in your British climate.

Cheers, Greg

Erik van den Ham on February 17, 2009

Very beautiful this Swainsona, Ian and like most peas, this one is poisonous too. Love those dark red flowers which would have matched the colors of the wedding bouquetperfectly.

My friend who's currently travelling Australia is now at Rosebank (near Lismore).

Greetings from the Netherlands, Erik

EcologistGreg on February 17, 2009

Erik, I hope they are staying dry. The areas north and south currently are having extensive floods.

Cheers, Greg

Ian Stehbens on February 18, 2009

Yes Erik,

Like Greg, I am also interested in their well being. I trust that they have had locals to stay with at Rosebank, for recently there has not been much movement in the area lately because of the floods in the Richmond River, and in other coastal valleys in that part of the state. The floods are now abating.

And thanks too for posting the kangaroo paw flower arrangement.

best wishes,


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  • Uploaded on July 14, 2007
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    by Ian Stehbens