AusBonsai

DO IT NOW
Start Your Root Over Rock

Yes, start it now before you are old. Nick down to your nearest nursery, find a nice rock and a trident with movement and get your root over rock going. Believe me, these days it is easier to find a young trident with movement than a decent rock to put it on but The Chase is fun.

Consider that in just under a squillion years your by then robust trident will have developed substantially so choose a rock that is still going to poke out under a tree much thicker and more imposing than a sapling. Something is lost in the translation when the roots grow to hide the rock… that defeats the purpose of the exercise.

NEVER plant your tree on top of the rock. That is artistically unsound and few seeds find enough nurturing when fully exposed to the elements. Try placing it a bit on the side, play around with the best placement. If your tree has movement your rock should compliment that. Some suggest growing the sapling in a cascade type container for a year or two to encourage the roots to grow down and then, before they are set in their ways, arrange them over your rock. Most of us just attach the tree to the rock and skip those extra years. It is a good idea but hell, life is not forever.

It is important to get your roots as close to the rock as possible… really up close and personal. Tridents and privets will, over the endless years, mould their roots to their rock until the roots look as tho they have melted down the sides and this is what all the work is for. An elm will NEVER do this. Elms can be separated from their rock at any time. By year two a trident or a privet has staked a claim on their rock and you can lift the tree and the rock will come with it. Try that with an elm AFTER you get your feet out of the way so when the rock slips easily away you don’t get damaged toes. It is necessary to affix the roots to the rock. Super Glue is not recommended so a stout twine is good for this. It will hold the roots and the rock together while you plant and gradually disintegrate while the soil holds the roots next to the rock. This eliminates any marking on the roots when they thicken. If you want a stronger attachment use plastic twine. DONT use Vet Tape. Simply DON’T. Yes, it does a great job. Yes, it doesn’t hurt the roots as they grow through it. YES, it is a picking job for years afterwards at every repotting trying to get it out. It is NOT worth it. Twine is fine. If there are areas where the root is stillnot in contact with the rock then lodge a small stick under the twine to flatten the root to the rock.

Pot your RoR in a large growing on pot and let it grow on. Good if you can get it in the ground for that added growth spurt but hard in city areas. Whether in the pot or the ground, lift it each year and check the roots. You know that Year Two will be insufficient time, even Year Three. The roots are starting to meld, the rock is definitely in their grasp, but it is far too soon to expose the roots so put the bonsai pot back on the shelf.

I have had this RoR in the training pot for 3 years. This repot I have put the bonsai pot back on the shelf, put the tree back in the training pot and cut up another plastic pot to make a collar so I can get soil even higher over the nebari to try to get more development.

My Port Jackson was a credible RoR after 4 years but the trident is slower to develop and once you uncover the roots and expose them to air they will not expand rapidly. It is worth the additional ages to keep them covered until they are really melting down the rock. As the upper roots develop you can lower the soil level each year until you have fully exposed the roots when they have attained the stage you are after.

This is not a rapid creation as I am annually learning. My three year estimate has gone out to at least five to six years after today’s repot. After I exposed the roots I repositioned some so they were artistically better place, removed some crossing roots, wedged small sticks in a couple to keep them in the place I wanted and made sure the soil was carefully put in and tightly compacted to keep the roots close to the rock. The collar was put around the tree and more soil added.

This year I am maintaining a fertilizing regime – one week fertilizer, the next week SeaSol or another root stimulant. I want this tree to need Weight Watchers when it comes out of the pot for next year’s prune and inspection. You can’t be too picky about keeping the tree in shape. While you want to control the branch development and placement you want a lot of leaves so the root growth powers on. There is a branch I want to remove from this trident RoR but not this year… I want its added feeding to increase the root development. Maybe next year.

In the end the exercise is definitely worth the wait and the time needed. I can well understand why one local master insists that all newcomers should start a RoR immediately so as their bonsai skills are developing so are the RoR roots.

This is the trident that sparked this article. I was hoping to start showing the roots before I inspected the growth and sadly put it back in a training pot and even collared it to increase development.

Thanks for the motivation

Good read good luck

Cheers

Jas

Keep us posted

Great suggestion, and I thoroughly agree that finding a suitable rock is the hardest part. I have a couple of PJ figs that I started last year. I went to my local fruit n veg store and got some of the foam containers with lids (and no holes) and I taped the lid to it with packaging tape. I then got my saw out (a knife will do, but be careful) & cut one side off so that when it is standing on the un-cut end it makes a nice deep grow box. I then got a piece of bamboo I had in the garden and used it to punch holes in the base for drainage. Then it was a matter of filling the box with potting substrate and your tree/rock combo. I am hoping to do that with a trident or two next year when my cuttings are a little bigger (and when I find more suitable rocks)

I would love to see some other RoR progressions and hear of other techniques.

hmmm, if I get a few trident seedlings this year I'll have to start looking for a decent rock

Hi Mela Quin,
I love R.O.R and have way to many on the go at the moment .I was re-potting some Maples today and took a few snaps of some of my first attemps.I made the beginers mistake and placed the tree on top of the rock. .I tend to neglect my Maples as they are in a shaded hard to get at spot.These Tridents are left to there own devices ,although it is getting time for the trunk chop.The second is a Trident that i fixed to a piece of sandstone ,it to could do with a chop. I have been using Grafting tape and find it OK.I have since found some better rocks, a real effort just to find them.
Great post, Cheers John.

Very timely article and very well written ! thanks for this it has been bookmarked

Barry

To Boom64 and everyone else

In a few years you won't have RoR because the roots will cover the rock but you will have an impressive nebari that today looks like thick cream pouring from the trunk. How superb. Since I can't see this as a visible 'root over rock' in a few years, can you pry the rock away now that it has served its purpose to create that wonderful nebari. It would reduce the weight, not that the rock looks big .. but still.

To me you have used one method to create something else and it is so good. And your radiating roots... well done.

Actually, it is easy to visualise a seed sprouting in the ground and over the course of its growth it happened to land on soil on a rock and the soil eroded away so it is 'on top of a rock' and natural. But for a more upright rock where the tree would be clinging it would not be so realistic.

The other thing about this particular tree, with the roots SO impressive it is good that the rock is SO boring but if one is going to plant on a flat rock - search for an interesting rock where the boring bits can be hidden by the nebari and the interesting bits highlight the composition.

Thanks for the detailed expose on Root over rock plantings Melaquin. I really love the combinations and spent a lot of time experimenting. After lots of work with root over rock I'll add the following comments:

1. Like growth habits above the ground, different trees have different root growth habits too. Chinese elms have a tendency for few roots to grow down. Tridents and liquidamber have a strong tendency to grow surface roots. Root habits will influence how roots grow on a rock. Melaquin has already noted that trident roots are quick to spread out and meld with the rock while elm roots take ages to do so.
Tridents placed root over rock then buried will produce lots of new roots heading out into the mix, sometimes at the expense of the ones clasping the rock. For reliable roots attached to rock trident roots need to be confined and forced to grow down the surface of the rock.
Elms, figs and callistemon are some I have tried that do not have this issue and can be grown more easily without the need to confine the roots.

2. Rocks tend to act as wicks and suck moisture out of the ground in warm weather. Root over rock and trees planted on rocks and slabs will dry out quicker than other plants. Need to monitor moisture levels more closely than other trees. i always soak the rocks before trying to attach the tree so the rock does not dry out the roots.

3. To get a good root/rock arrangement have several rocks and/or a number of suitable trees to try. Some just will not fit the rock properly so you need at least a few to get a good fit.

4. The old Japanese technique of muck (clay/manure mix) to hold roots onto a rock has not worked well for me here. More often than not the roots pasted onto the rock with muck die and new ones grow elsewhere.

Here are a few of my other root over rock tridents. this final one is one of my early attempts. Not much of a rock and the roots are not clasping it really well but it does have good ramification.This pic from 2001 I have just dug this year's crop of root over rock tridents from the growing beds and again there are some great ones that will be ready for sale later in the year.
Only 1 left from last year.