ok mariella,

had to check out what "allelopathic properties" meant, yeh righto' this is basically a wives tale well maybe not so with a tree that has those abilitites out in the wild protecting its right to survival by keeping out any competitors, but once that said tree is chipped and you apply it as mulch, that we have found is the end of story of those "allelopathic properties".

our eucalypts are charged with this ability and yes in certain circumstances ie.,. dry low rain fall and a large euc' tree no other tree is found growing within it's drip line(produces chemicals in its leaves that prevent other things like competative trees growing), grasses and other small plants yes as the tree probably doesn't see them as competition for the deep water that may be scarce in the ground.

so as you get into higher rainfall areas you see more lush growth of the grasses etc.,. under the euc'/gum trees as they create a system of recycling and holding moisture trapping falling dew from the trees leaves for the benefit of not only the tree but the other plants as well this includes the decmposition of the trees leaves. and in high rainfall area where the gum tree has plenty of available moisture then you get the shrubby and smaller trees growing nearer the bigger tree.

we have used lots of chip from tree lopper most would have had gum chip and leaves in it and never had any issues of anything just turning its toes up. when we lived in a medium rainfall area and our lushest grasses grew under the gum trees.

len

Here is a link that might be useful: lens garden page

What len said ... I have ZERO weeds growing under the mesquite trees, but shredded they make fabulous mulch and compost.

The competition controlling chemicals are produced and excreted by the rootlets, BTW, not the leaves.

The allelopathic chemicals are also located, but to a lesser degree, in the leaves. Species vary widely in how they 'distribute' their toxins. In Ailanthus, the roots (not just the exudates but the root wood and bark) have the strongest effect with foliage providing fewer problems.

So, if I understand right, two of you think it would be ok to use the tree of heaven as mulch but zhizo disagrees. Rhizo, what would be the worst I could expect from using the tree as mulch?. It doesn't seem to be anywhere as toxic as the black walnut, from what I've read. Is that true?. And what does that mean from a practical point of view?
Thanks, everybody.

The "Tree of Heaven" is a trash tree that seeds prolifically. We have many seedlings of this tree growing in the church yard, almost as much as we have Nightshade, because there is a full grown "Tree of Heaven" across the street. Where these trees grow, at the church or anywhere else, I have not seen any evidence of any allelopathic properties, they share growing space well with anything, althought they grow so fast they crowd out the more desirable species.
The only problem you will have using this trees chips as a mulch is the possibility there may be viable seeds in that mulch.

Thanks a bunch, kimmsr. Would it help the "viable seeds" issue if I aged it a year? Otherwise, I would have to periodically patrol the mulched area to check for unwanted seedlings, or save the mulch to incorporate into the compost.
Thanks again for the feedback - much appreciated.

don't think rhizo disagreed but anyway moving on, if it is the viable seed you are worried about there again for us when a seedling popped up we pulled it in some cases the seedling was desirable we potted it.

composting may not get rid of all viable seed.

len

The only thing I have seen on the viability of "Tree of Heaven" seeds was someone reported raking up some leaves that had accumulated for many years and sudddenly several of these trash tree seeds germinated and started to grow, so I'd suspect that these seeds remain quite viable for some time although hot composting should render them not viable since they do not have a hard cover.

Many thanks to all of you. I think I'm feeling comfortable now with using this tree as mulch, but even if I compost some of it, since I do have a ton of it, I'll be careful to watch out for the seedlings. One thing for sure I don't think I would ever want it to grow as a tree any wheres around me.

I didn't disagree at all, but just wanted to clarify the whereabouts of allelopathic chemicals within this particular plant. I'd probably use mulch from the primary tree body, too.

By the way, the allelopathic properties of this plant are well documented. The primary chemical, Ailanthone, is being studied for its potential as a broad spectrum herbicide.

Just a specific note about Ailanthus- be very vigilant about starts-they eventually form an underground network they all feed from. So if you're trying to eliminate one, the others all lend support.

Google Tree of Heaven for info on the underground root system and time of year when they take poison down to their root system i didn‘t know anything and with council’s permission cut down the one tree I had. Council didn't tell me it was a weed. i now have it popping up everywhere. I now know what to do with the help of Google.