Wednesday, January 14, 2015

Cottage Research: Killing Tradescantia fluminensis

The following is the result of about 6 months of experimentation in organic, quick and simple ways of killing the incredibly resilient weed Tradescantia fluminensis (Wandering Willy, Wandering Jew) a serious pest here in Wellington, New Zealand. My aim was to find a way of killing the plant once it has been weeded/collected so that it can then be recycled back into the garden as compost or as mulch, this is not  an attempt to find an organic way of killing the plant on the ground where it grows.

The best method was found to be immersing the weed in a tub filled with a combination of worm castings from worm farms, the liquid produced from the worm farms, combined with up to 1/3 water (to make the solution go further). The Tradesantia is then weighed down so that it is totally submerged and left in the solution for 10 days, the solution being stirred every few days as it tends to settle. After 10 days the weed is laid out in the sun for 3 days, it is then completely dead in my experience.


1. Tradescantia fluminensis before treatment...the world's its oyster.

2. Tradescantia fluminensis placed in a large plastic tub filled with approx 1/3 worm castings, 1/3 liquid form worm farms 1/3 water stirred to become a thick dark mixture.  The less water the better.

3. Tradescantia fluminensis weighed down with brick so that it totally submerged.

4. Tradescantia submerged. So far this solution has not produced any notable smell, a consideration in urban areas . This was expected as worm farms are often kept indoors and usually produce no noticeable odour. 

5. Tradescantia left for at least 10 days, covered to protect from rain. Stirring from time to time was assumed to be necessary because solution settles becoming fairly clear near surface, I did not try not stirring it (you could experiment with shorter periods if in a hurry, I found after 5-7 days about 1% of plants survived, these could be put back in for another go since they like it so much).
6. Wandering Willy after removal from tub, the leaves are gone/dead but note the stems are still green. 

7. After 2-3 days in the sun the Tradescantia remains are completely dead. It seems to be necessary to keep the stems completely dry, in experiments some stems soaked in water for 10 minutes revived. In limited experiments drying indoors away from sunlight appears to be effective but takes much longer.


Use of Remains in Garden.
I have not yet experimented much with safety/appropriateness of using the resulting dry remains (presumably mainly carbon) directly in the garden. It is usually recommended worm castings should be added as a thin mulch in the garden (too much kills or weakens most plants) the same advice probably goes for this stuff , though I dried a reasonably thick layer of it out on top of other vegetation, it had no noticeable effect at all. I suppose a build-up of toxins over a long time might be possible if used over & over in same place, but it being washed away by rain seems just as likely.  

A compost heap is recommended in various places on the net as one of the few safe places to dispose of the liquid from worm farms. From this I'd infer putting the Tradescantia remains into the compost heap, especially in high rainfall areas, is probably fine.
 
I also tried putting a few remains into the worm farm, the worms seem much less enthusiastic about eating it than Tradescantia that had been through a blender, but after about a month it was gone, apparently largely with help from other minute beetle-like organisms also in the worm farm. Presumably the worms weren't crazy about eating it either because it was covered in their own waste or because it was so dry decomposition took place much more slowly (tiger worms eat rotting stuff). Soaking remains in water before putting it into the worm farm seemed to result in it being consumed/destroyed about twice as quickly, which might support either theory. More experimentation is needed here. 
 
Why does it work?

I don't know why it works. Supposedly worm castings are high in salts, this might explain why they dry up so quickly when left in the sun. Apparently worm waste is somewhat, but not very, high in nitrogen, reportedly nitrogen from human or animal urination on or near plants can sometimes kill them. 





Footnote: Some rejected or abandoned means of killing Wandering Willy.

Commercial Blender- effective but very noisy, fairly slow & tedious unless you can find a huge blender.

Chopping by hand with knife into very small pieces (less than 1 cm) effective but not as effective as blender, seem to re-sprout under certain unclear circumstances, probably access to water, very slow though can be calming

Placing in black plastic bags in Sun to "cook"  ugly, not practical if you have limited space, may take years, same if bags kept in shade or complete dark.

Immersion in water. Effective but may take many months.  

Cooking in conventional oven. Only effective for very small quantities, large, practical quantities do not cook evenly.  Same would go for a specially made solar oven which a few people have thought of on the net but no one's tried it seems.

Immersion  in boiling water. As little as 10 seconds in boiling water kills Wandering Willy but this only works with small amounts held under with tongs, large amounts take much longer to return to boil. Protective clothing probably needed if repeatedly placing weed in boiling water over long period.

Immersion in human urine. More effective than worm castings and liquid mix, as little as 2 days soaking kills Wandering Jew, though 3-6 days better. Treated weeds also need to be kept away from water for several days once removed to dry out, otherwise they may recover. This experiment was small scale with small sections of weed, also source of urine was a meat eater, supposedly more toxic/high nitrogen. Urine smells and is likely to be unacceptable to neighbors and possibly officials, though this may not be true absolutely everywhere or in a more enlightened greener future. Unknown disease potential.   

Worm castings & worm liquid used separately. I found combing worm castings (with water) and worm farm liquid was considerably more effective than using either on it's own but experimentation was not especially extensive & could be explored more.

Food for humans & animals. A number of animals will reportedly eat Wandering Willy including chocks and Guinea Pigs. Aside from the fact that the nutritional content of this plant seems to be unknown, I did not try this method because of lack of space & aversion to slaughtering animals. Apparently one solitary source (The Encyclopedia of Edible Plants of North America(Couplan 1998)) states the young leaves can be eaten by humans when cooked. They are palatable in my experience, but that still leaves old stems and leaves, in addition to likely oversupply of edible parts.

Hot or Fast Compost Heaps, with very high ratio of carbon to nitrogen materials, turned daily or very frequently, have been recommended on the net for this plant & probably work (normal compost heaps are of course completely ineffective against this plant). I haven't attempted fast heaps as they seem like a fine art & it would be labour intensive turning large amounts of compost made from this prolific weed. Also Tradescantia is "green"/high in nitrogen so about 30 times as much "dry"/carbon materials would need to go with it to make the heap work, which would probably not be readily available. 


Finally a few interesting facts stumbled over: 

Spraying all of the above fluids onto Tradescantia using a commercial trigger sprayer had absolutely no effect, both on the ground where it was growing and indoors with cuttings, it's possible non-organic commercial spays are the only way of killing it where it's growing. 

I had to tell my dog not to lick the worm casting mix off the weeds placed in the sun, she really seemed to like it. I didn't notice her vomiting later on or becoming sick, perhaps worm farm waste could be a temporary emergency dog food if supplies are cut of in a disaster, dogs are well known for eating various kinds of feces, apparently without harm. I'm saying maybe this is a possibility, I have no expertise in this area & am not qualified to make any recommendations.

Also my pigeons started using the dried Tradescantia as straw to make nests once it had been dead for a week or two.  







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