Potting a little lower is the best defense against runoff pulling soil. You should have reduced the bottom of the root mass another 1" to 2". Soil should be level or 1/4" or so below the rim. That makes watering less destructive and more productive, since all the water goes through the pot and not down the exterior.
At this point, sphagnum moss spread thinly over the top will help keep the soil in place as well as keep it more humid underneath for new roots. A watering wand or similar that has a fine to extremely fine spray also helps tremendously.That's water under the bridge though
Typically a couple of months. I've left it on some repotted trees all summer in some cases.
Thank you. I remember asking about that really early on in my bonsai journey and a certain expert's opinion was to expose the nebari from day one, even on young material. I did not and still do not understand how exposing the roots could encourage development of nebari.
Upside is that they start barking up earlier and therefore they match up with the trunk at a younger age.
Most root masses are like that. They require sorting and reduction, particularly if they're an entangled mess. Most beginners aren't nearly as aggressive as they should be in addressing that. Maples can handle pretty hard reduction. I use a saw to eliminate the bottom two thirds of most maple root masses at repotting, then sort through the remaining roots, particularly at the surface
Indeed.
Given my root mass block of wood reference, until your response, I was a bit embarrassed to admit that in my frustration, I did break out a saw and cut the root mass block of wood in half, however I did not cut enough for tree to fit nicely in the pot. I now have four Chinese Elms to do. I believe I can do them with a bit more confidence. Living and learning I suppose.
Don't be embarrassed. I have a large trident maple that had a significant nebari that was buried under a mass of roots for years. Didn't know it was there until I learned from watching someone else how hard they can be root pruned. I discovered the nebari underneath two inches of overgrown roots one year when I got more aggressive with a saw and shears. Same with some JMs-although you have to be a little gentler with them
Second this approach. Prior to this point keeping the nebari covered aids in thickening the thinner roots near the surface to improve nebari. It does this by maintaining better moisture levels near the surface. Very important in deciduous development of species like Maples, Zelkova that are known for flatter wider nebari forms.
