I have a pretty decent size azalea plant driftwood (w/root ball) in my 45g tank, makes LOVELY drift wood. Before anyone shouts "Hey those are toxic!" just know that I was aware of that before I used it
However, the toxicity is (so far as I know) against animals, and I've had absolutely no problems so far with fish death. Everything is healthy as a horse.
But plants are growing slow. Partly due to lack of CO2, but I just want to try to rule out the azalea driftwood possibly causing some sort of inhibition of plant growth. See my link in my sig for the setup, but suffice it to say there is plenty light and plenty of ferts in the tank. And using fairly heavy doses of Excel has profited nothing but killing off some BBA. Nearly no effect on plant growth.
Everything in the tank is surviving, but growing oh-so-slowly.
To treat it, here is what I did.
1) Baked it for 5-6 hours at 275-300. Heat theoretically would have neutralized many toxins.
2) Soaked in water, outside, for 5-6 months. Water change frequently (maybe twice a month).
3) Scrubbed, washed, and partly de-barked, but not totally.
4) Attached to a 1/2 thick, 5X5" slab of scrap Corian/acrylic to hold steady.
Here is a pic: