What should I use as a barrier to keep tree roots out of a flower bed?

I am going to dig up the flower bed in order to bury the barrier.


BTW I know about weedblock, but I think something stronger would be better.





Thanks!

What should I use as a barrier to keep tree roots out of a flower bed?
Here are a few professional websites. Most of this you can purchase from a Porfessional Landscape Supply company like John Deere Landscapes:





NDS -


http://www.ndspro.com/cms/index.php/15-L...


Deep Root-


http://www.deeproot.com/template.php?sec...


BioBarrier


http://www.biobarrier.com/
Reply:water would do the trick.





if you water deep, the roots will grow deep to get the water.


if you watering shallow, the roots stay near the top of the ground.