I have an excess of "tree of heaven" on my property. It took possession before I knew what it was. I understand it has very strong allelopathic effect. My question to you is have you ever used any strong allelopathic wood or plants in your hugelkultur beds and if so, did they cause a problem. I'm not sure once cut and dried for a year or so that the chemical effect would still cause a problem. If not, I would have plenty to start many hugelkultur beds.

Thank you.

I've never used allelopathic woods in my hugelkultur beds and I would have serious reservations about doing so, even if the wood was very old. Considering how long of a timeframe one is looking at in a hugelkultur bed, it just doesn't seem worth the risk to me.

The wood isn't going anywhere, nor are you. Create a test bed with alopathic wood and test fire it for a couple years.

Thanks for your suggestions. Yes, perhaps I will do a test bed and put some native wild flowers in the bed.

Hello, i really need some help here, i want to ask question regarding allelopathy, so i've done experiment on Chromolaena odorata leaves extract, and i've tested it on the the germination of Amaranthus tricolor seeds. However, problem is my result shows that, 10.0% concentration of leaves extract application shows better result in seed germination compared to 7.5% extract of leaves. can someone explain this to me please, i'm really desperate to know.

@anazoh, Welcome to ATP.

Whew, that's a complicated question.
I did a quick Google search and found several articles like this one which may help to explain:
http://www.idosi.org/ajps/5(4)...

Here is another one:
http://www.regional.org.au/au/...

@greene @anazoh That first link doesn't work if you just click on it. But it does work if you copy and paste it. (For some reason, the whole address isn't highlighted as a link.)

anazoh said:Hello, i really need some help here, i want to ask question regarding allelopathy, so i've done experiment on Chromolaena odorata leaves extract, and i've tested it on the the germination of Amaranthus tricolor seeds. However, problem is my result shows that, 10.0% concentration of leaves extract application shows better result in seed germination compared to 7.5% extract of leaves. can someone explain this to me please, i'm really desperate to know.

Do you know for sure that Amaranthus is supposed to be susceptible to its allelopathic effects? If not then my first thought would be that it is not, same as not all plants are susceptible to the juglone from black walnut for example. In that case the explanation may be that there's something in it that stimulated the germination or it is coincidence. How many seeds were in the test batches? Did you have an untreated contol?

Edited to add - by coincidence I mean that the 10% versus 7.5% difference may be coincidence but that somewhat depends on how many germinated and how many seeds were started.

BTW I had trouble finding this question again, I think it was a separate thread originally unless I'm dreaming. When I came back to answer I finally found it tagged on to this thread. @anazoh welcome to ATP and I hope you find your way here.

Hey, thanks for the answer btw, yeah, i've only have time replaying to this post now, i'm sorry. I think it's supposed to be susceptible as the 7.5% leaves extract of Chromolaena, do have very significant effects on the germination success of the seeds, where many are seems to not germinating. i do have control ( using distilled water). and i've tested 30 seeds in each treatment, with 3 replicates. Thanks for the warm welcome

I found the same Australian link for research on the allelopathic effects of Chromolaena that Greene gave earlier in the thread, which says:

"Weed seed germination was inhibited by siam weed extract more than crop seed germination. Maize seed germination was not hindered by siam weed extract while on cowpea and soybean, 14 and 8 percent reduction in seed germination, respectively was recorded when compared with the untreated control. Percent reduction in germination in siam weed treated with the extract was 87 %, when compared with the untreated control . Siam weed extract had some inhibitory effect on soybean growth at the later stage of crop growth, while the growth of maize, cowpea, tridax and siam weed itself was stimulated by siam weed extract."

Allelopathic Effect of Siam Weed (Chromolaena odorata) on Seed Germination and Seedling Performance of Selected Crop and Weed Species

This confirms that not all seeds are affected by it, since corn (maize) was not.