Callitris on rock?

[PWC]

Looking for advice, found a few interesting rocks recently, and thought I might try planting some juvenile Callitris onto this rock.

IMG_1927 (Large).JPG

I am not sure if they would be suitable, I think it could look good though, but is it worth having a go?

[shibui]

I think it is worth trying. Calitris grow in some pretty rough places so it will be more about your skills and care than the trees.
Are you planning roots confined to pockets or roots running down the rock to soil below?

[PWC]

I think it is worth trying. Calitris grow in some pretty rough places so it will be more about your skills and care than the trees.
Are you planning roots confined to pockets or roots running down the rock to soil below?

There are two pockets that have natural drainage hollows through the rock, one goes all the way to the base. My thinking is to plant the larger one in that and allow the roots to eventually find their way to the base and into the subsoil. One would be placed about half way up on the side, it also has a hollow that drains through the rock,but not to the base. The third was to be coming from ground level, possibly from the hollow in the front center.

[shibui]

The holes through the sandstone can be great but also has problems. As the tree and roots grow and thicken it will put pressure on the rock and eventually crack it. If the rock is strong enough to resist the force of growing roots circulation will eventually be cut off and the trunk probably die. that is far less likely as roots exert huge pressure as you may have seen where they lift up slabs of concrete.
I threaded some fig roots through holes in sandstone. It only took 2 years for them to break off the highest parts of the rock. Lesson learned for me.
Callitris are much slower growing so you will probably get much longer to enjoy the bonsai.

[PWC]

The holes through the sandstone can be great but also has problems. As the tree and roots grow and thicken it will put pressure on the rock and eventually crack it. If the rock is strong enough to resist the force of growing roots circulation will eventually be cut off and the trunk probably die. that is far less likely as roots exert huge pressure as you may have seen where they lift up slabs of concrete.
I threaded some fig roots through holes in sandstone. It only took 2 years for them to break off the highest parts of the rock. Lesson learned for me.
Callitris are much slower growing so you will probably get much longer to enjoy the bonsai.

Pretty sure it's not sandstone or limestone, I tried to drill one of the pieces I collected with a masonry bit and found it extremely hard. Thanks for the feedback as always much appreciated.

I hadn't considered the root constriction scenario, not sure if there is a solution. May have to consider root pruning annually to prevent the issue occurring.

[SquatJar]

Could put some flyscreen at the top of the holes. Allows the drainage to continue but stops the roots growing down and applying pressure?