What happens to the roots that hit a barrier? Do they die or reroute?

When roots hit a root barrier, they typically do not die instead, they reroute.

Here’s what happens:

When a growing root reaches the root barrier, it recognizes a physical obstruction. Since roots naturally seek paths of least resistance toward water and nutrients, they won’t force themselves through a tough, impermeable barrier (like HDPE plastic).

The root will turn and grow laterally or downward, depending on the barrier’s depth and design. This redirection is what makes root barriers effective—they steer root growth away from sensitive structures like foundations, pipes, or sidewalks.

If the tree is small or doesn’t find a new favorable path, the root’s growth may slow temporarily. However, established trees usually adapt and continue growing in other directions.

Roots that hit a properly installed root barrier will reroute, not die. This redirection helps protect structures without harming the overall health of the tree. However, if the barrier is shallow, has gaps, or is installed too close to the trunk, roots might find a way around or eventually push through over time.