Why does covering stumps with wood ash prevent eucalyptus regrowth?

I must have read somewhere that covering stumps with wood ash prevents regrowth. So I tried it after cutting down two eucalyptus/gum trees in the yard. Normally, these guys would shoot right back up. Not this time. In fact, now I have bermuda grass/gramilla taking over where the stump was. It grew right on top of the ash with no dirt or anything!

What I did was cut the tree down to the ground as low as I could and on top dumped ash mixed with water (to make a nice paste). Boom! No regrowth and no having to grind stumps, etc. People here usually say you have to drill into the stump and dump in chemicals.

But why does the ash and water mixture work?

Ash and water mixed make lye, which is highly alkaline.

That surprises me, I walked through an area, in Queensland, between Brisbane and Toowoomba where a fire had burned for severl days. The ground had a foot of ash, after a good rain, up came the gum trees. I never saw a gum tree that I didn't want to keep growing.


Elliot, What are you doing in Uruguay?

That's a good question Richard. I'll let you know when I find out!

Meanwhile, the ash mystery continues...