pumice for ROR

[Joshua]

Had anyone used a large piece of pumice for ROR? If so how was the experience.
Thank you.

 

[Redwood Ryan]

Had anyone used a large piece of pumice for ROR? If so how was the experience.
Thank you.

What species would you plant on it? The pumice I deal with, while it may be small soil sized, is easily breakable, so a species with a vigorous root system may break the rock.

 

[edprocoat]

Joshua I wasted two years with a juniper on a piece of large red landscape pumice. It was all I could do to drill some anchor holes in it as it was very hard. I spread the roots of a healthy Juniper over it and then covered it with about a half inch of soil clay mixture then wrapped it in burlap. After two years with very much growth of the juniper I removed the burlap and the plant fell of the rock. After looking at it I noticed how the roots seemed to grow away from the pumice and at first I thought maybe the pumice was bad for growth or covered with some kind of defoliant.

I thought about this some more and it dawned on me that maybe the pumice with all the air passages in it acted like those screened grow boxes where the roots self trim when they hit the air. I decided to see if this had some merit so I soaked the rock with water and hit it from the bottom with an air hose and the air blew out through the top and all the sides. I now think that was exactly it, the air flow in the pumice kept the roots away from the rock. Take it for what it is worth, but as for me I would not waste the time trying to grow on pumice.

ed