Rose Rock for Root over Rock

[Aaron the Great]

Hello Earthicans!

I have never tried a ROR before but I once saw one on the internet!
I'm wondering if this rose rock has the potential for a root over rock planting.





This is pics of the four sides of the rock. Its roughly six inches in diameter and bout three inches tall. The bottom is roughly flat. It has red sand that is mostly formed into sandstone but not quite, that is the slightly different colored sand that you see in some of the grooves. It can probably be removed by a rotary tool to enhance the groves. It is currently the second largest Rose Rock in my collection.
I'm no expert in this but I was thinking of something evergreen to off set the redness of the rock. I do have some freshly picked seed pod/ berries that were picked from an Eastern Red Cedar (Juniper) about 50 feet from where this rock was collected. I could be cool.

Anyway will this make a decent root over rock or do I need to keep on looking?

 

[Gabler]

How well do they hold up to the freeze-thaw cycle when wet? I've never held one before, so I don't know how hard or how durable they are. They might be well-suited. I don't know. I just figure it couldn't hurt to bring that up, since you wouldn't want your rose rock to crumble into rubble due to seasonal weathering.

 

[Aaron the Great]

I would think that it would be just fine but anything is possible. This is a sandstone and is formed naturally in this area. I found this rock in a outcropping of smaller rose rocks in a field so who knows how long it was outside before I wondered upon it.

 

[Michael P]

Here is an article from the University of Oklahoma https://www.ou.edu/ogs/generalinterest/rose_rocks It does not discuss freeze-thaw resistance but since the mineral is found on the surface it can't be too fragile.

 

[Aaron the Great]

I don't think that it breaking from freeze thaw will be an issue it's basically a uniquely formed sandstone. . I'm interested in will it's shape be good or bad for root over rock.

 

[Michael P]

Sorry, got it!

One of the characteristics that is traditionally valued in root-over-rock is roots that cling very tightly to the stone. The rose rock has a very complex shape and it will be difficult to achieve really tight contact between root and rock.

 

[rockm]

In short - no. Not a good rock for root over rock. Too low too small. Not enough rugged character. It will be a distraction to any tree out with it.

 

[Aaron the Great]

Ok thanks for the feedback. I will keep my eye out for a better rock.

 

[SeanS]

How hard is it? It looks quite “sandy”, if you rub it hard with your fingers does it wear down, does sand come off of it easily?
It’s an interesting shape but as mentioned it looks like it may take attention away from a tree placed on it.

 

[Aaron the Great]

It's pretty hard, I wouldn't want to get wacked with it. You will have to hit it pretty hard with a hammer to chip it. Other rose rock can be brittle but that is because of the thin pedals. It isn't granite but it will take some effort to damage it.

 

[Shibui]

I agree with @rockm I looked at the picture and tried to imaging how the roots would flow down over the rock. The shelves are going to make good root-rock contact difficult.

Rocks for ROR need to be very strong. Not only durable for cold/hot cycles. Don't underestimate the power of roots slowly growing. My first Ficus ROR was on sandstone. The roots kept breaking sections of the rock as they grew.

ROR is possible with low rocks but I think the most impressive ROR are on a taller rock which gives the impression of a mountain or cliff. Taller rock shows off the roots better which is the whole point of ROR isn't it?
The rock also needs to be large enough that the tree does not overwhelm the rock as the tree thickens and grows.

 

[rockm]

It's hard to explain, but the character of the stone is what disqualifies it for me (the small size is second, a fast growing would cover that in less than a decade give or take).

The character isn't in line with what is prized for root over rock stones. For a reference (And it hardly the only stone to use) do a search on Ibegawa rock. It is used extensively for landscape plantings and ROR. Sometimes it's carved into extreme shapes but it works very much "on its own" because it has weathered interest of real stone. That is a quality to look for in ROR. Natural looking not really all that exaggerated or out of the ordinary. The stones in this article are Ibegawa (although the trident "dragon" bonsai second from the bottom isn't.)

While your stone is great for a collection of unusual rocks, it would be distracting and alien looking with a tree planted on it. It would be more novelty item than bonsai. Also, this is what happens when a tree outgrows the stone it's planted on. This trident maple is at the National Bonsai and Penjing Museum. It began life on the rock in 1916 in Japan. While over 100 years of cultivation its owners have worked to keep the tree in shape with the rock, the tree is beginning to overshadow the stone a bit. The composition still works, but the point is you have to look into the future a bit. Not 100 years, but certainly five to ten. This stone is pretty large. The smaller the stone, the quicker it will be overwhelmed. Fast growing species shorten that time line even more.

 

[Aaron the Great]

Thanks for all of the help, this is why I posted this question for it is better to find out now than trying to figure it out as I'm trying to put a tree on the rock. Thank you a lot.

 

[Shibui]

Only around 30 years old but already the tree has outgrown the rock

This one I'm prepared to keep working on, even though the rock is almost swallowed by the roots. In this case, the rock is not the most important or best part of the arrangement



This one has reasonably good tree/rock size and arrangement


A bigger ROR. Need to allow for weight when creating ROR. This one is only just manageable for an old fart alone. When it was dug from the grow bed, many years ago, the volunteers dubbed it Root over Boulder when they finally lifted it out of the hole and that rock is not really all that big.


Ficus roots just keep on thickening, even in a pot and even ROR.
This one was sold many years ago. Photo from 2007.
The roots kept breaking exposed bits of rock off and finally there was so little rock showing it just wasn't a ROR any more. No scale in the photo but the top of the tree is around 2 feet above the pot.