Limestone is fairly weak, the roots won't give up, if they want to go deeper
it may just take them longer.

But it's also going to depend on how that species' root structure grows.

The Live Oaks Gary mentioned have a very shallow structure, spreading out
wide but not going too deep. (They'll also interconnect with other live
oaks, which is unfortunately one of the methods that helps oak wilt
contaminate surrounding trees once it has set in).



"Paul" wrote in message
...
As an out-of-stater new to Austin (NW), I went out and bought a tree
last year thinking I could just dig a hole with my shovel and plant
it... Hah. Of course I was surprised when I hit solid bedrock 16"
down. The tree (a Drake (Chinese) Elm))was in a plastic container,
don't know how many gallons but it just fit in the 16" deep hole I
dug... So I set it on top of the bedrock and filled in (diameter was
about 3x that of the root mass diameter).

My question is, is it ok to put the Drake Elm on top of bedrock like
this? It's been one year, the tree looks great, but hasn't rooted
much. Am I going to end up having to dig out the tree after a few
years?

Thanks