Pumice for Root'o'Rock

[rodm]

Hi all,
A friend of recently gave me couple of large pieces of pumice. Has anyone used it for root over rock? Me thinks it may be a little soft or brittle once the roots start to grow, causing it to crumble. Any information and advise would be welcome
Cheers RodM

[kcpoole]

Far too soft IMHO
Same as sandstone. just falls apart under the pressure

Ken

[rodm]

That's pretty much what I thought,thanks Ken

[fredman]

Pumice is actually surprisingly tough. I have quite a few from softball size to the size of man's torso. I was very apprehensive about their strength when I first got them. Started off handling them with great care. I planned to hollow them out and plant mainly satsukis in them. I then went to.... had to know how strong they are, so I started "testing" it. I started dropping it from low heights and gradually went higher. I ended up at 2 meters and all it does is chip a little bit off. I knocked it with a rock several times but that only chips them to. The advantage they have is they are like a sponge. They CAN take pressure from the outside. I now have 5 satsukis planted in them. They can take an lot more punishment than a little bonsai root can ever put on them. I would use them as a root over anytime. Best is to drop it on concrete starting "softly" to see if it has a crack in it If it doesn't break then by all means go for it They are natural moss attractors though. After a while you don't see the pumice anymore. It'll be covered in moss...

[rodm]

Well fredman don't have to test it to much. Applied a little pressure by hand, it broke and crumbled. So on that I might give it a miss
Cheers RodM

[Andrew F]

If it werent for its lack of stability it would be one of the best rocks to use, I love pumice as a potting media.

[fredman]

Oh dear not good quality pumice that Shows me not all pumice are created equal.

[kcpoole]

Oh dear not good quality pumice that Shows me not all pumice are created equal.

Where do you get yours?

The only stuff I have ever seen is quite brittle and quite crumply when under pressure

Ken

[bonsaibruce]

I have seen some used as rocks with a tree. It is good to keep the weight down if you create a penjing flat tray style.
They may be full of salt, so soak before use.
Happy bonsai,
Bruce

[KIRKY]

I have a few, one I have drilled/hollowed out and I have planted a JBP along the outside with the roots going into the rock and down through onto a shallow tray. The rock itself looks like normal volcanic rock that you would use around the garden however it is very light. Not soft or brittle. The roots have been in it for a few years now with no problems. The rock itself is still sound and hard. I checked the remaining rocks that I have yet to plant trees into, they too are all hard but light weight. To do them serious damage I would need to hit them with a hammer a few times. Perhaps there are different grades of pumice/volcanic rock.
Cheers
Kirky

[fredman]

I'm in NZ Ken. They are abundant along certain rivers and lakes in the North Island. They are tough and will withstand anything as far as bonsai is concerned. To damage it one has to really go at it with bad intentions....
I even picked up a pink one the other day

[rodm]

Maybe, fredman, you should export some across to your cousins across the ditch; but not too much of the pink
Cheers RodM

[isimiyaki]

Hi The pumice is great for using in landscapes to either hold up earth or feature as it can be easily carved and shaped.
Since it is porous moss grows easily over giving it a natural look.

[fredman]

2015-12-14 14.21.40.jpg

Rod I can send you one next Valentines day. I'm sure Lovey would love a pink block in bathroom, to keep them heels nice and smooth

[kcpoole]

Now that is awesome Fredman
Love the pink ones.
FYI, the pumice we can by here that I se in soil mix is imported from NZ

Ken