"Warren" writes in article 74ffd.247265$wV.40076@attbi_s54 dated Mon, 25 Oct 2004 22:26:11 GMT:
How do they know there's water inside the pipes, or beyond the concrete?
Wouldn't the roots grow just as much in the other direction - maybe even
more if there was no resistance? What attracts them to the pool and
pipes? Smell? Visuals survalence from the branches, passed to the roots?
Can you fool them to think there's water in the oposite direction?

I disagree with the being attracted part (unless the pipes leak), but they
can definitely tear things up.

I had 2 willows (now, after a hellacious battle, 1). Both grew roots across
the surface of the lawn and under the sidewalk, lifting it up and cracking
it. Cracking a pipe would be easy work for willow roots.

The one that remains is a giant. It looks good from a distance, but close
up it's a mess. It's always dropping branches, and the roots are horrible
to mow around. It's getting the axe soon, in favor of some bamboo.

-- spud_demon -at- thundermaker.net
The above may not (yet) represent the opinions of my employer.