Looking for some insight into when to start exposing/uncovering muck from the proximal/base roots in a root-over-rock juniper planting. I have several air-layered junipers that I potted over rock in initial design last winter. All had plenty of root extension into the pots initially, and have recovered very well since the repotting. However, in all the the library videos on the topic, I see lots of “how to place on rock initially”, but nothing really on when/how to start exposing the roots later once they have filled the pot.
So if anyone has direct experience with this, or knows of a video in library that specifically addresses this, I’d much appreciate any comments.
Mike - I have done pines and maples and like to keep them covered for at least 2 to 3 years. The roots will thicken and clasp the rock better when kept covered. If I buried the rock, I often expose the roots when I repot to remove and/or redirect unwanted roots. I hen recover them with sphagnum and green moss for another couple of years. This also allows me to see something similar to the final form with a tree growing on a rock in a pot (albeit with the roots covered) so I can better style the branches. I figure a root over rock planting is 4-6 years from planting to full root exposure. - Marty
Thanks, Marty.
In the absence of any experience on my part, that’s a slower timeline than I would have pursued, left to my own devices. I was thinking more along the lines of starting to expose from proximally after maybe 2 years from time of original placement on rock, and gradually moving further down with each subsequent year. Part of my rationale is that, when first placed in their"paths" along the rock, the roots are basically multiple fine roots “bundled” together, and choosing a dominant root for each bundle, by pruning out lesser/weak roots (gradually over time) would encourage expansion of remaining selected roots. In your experience, do your trees essentially develop a dominant root in each bundle on their own? Or do the roots fuse?
In my experience with the pines and maples you sometimes get a dominant root and sometimes they fuse. Not sure how juniper roots will behave, but because they don’t close over shari very fast I would expect the roots to not fuse into a single root. However, set of roots that are tight against each other could look cool.
I think it is fine to uncover the roots to clean off redirect undesirable roots. However, I feel it is important to cover them back up, so they grow bigger and better attached to the rock. Early exposure of the roots slows their development.