My seedlings have grown very vigorously this year. Some have pushed a second flush of growth already formed whorls. Would it be appropriate to reduce these now or wait till spring?
I would reduce the whorl of buds as I described in the article now rather than waiting until spring. This makes it less likely you will get reverse taper at the node. I took the photos this week on a two year old tree.
If you get reverse taper anyway, wait until middle of spring next year and remove the growth to just below the whorl. The tree will send out needle buds. Thin the needle buds and re-start the sacrifice branch process. This will slow down the growth of the trunk significantly, but there's no point in having a large trunk if it's got reverse taper and other flaws.
Is there a rule of thumb on how to reduce the number of buds at a given node? There are several cases where I have 6 or 7 buds at the same location. What should I keep in mind when I choose which buds to keep?
Leave the central bud, which would normally be the largest, but sometimes the side buds elongate during the summer when a tree is very strong. Remove all but one of the buds around the central bud. You'll have to use scissors to remove them if they've elongated. I would keep one of the smaller buds on what you think will be the left or right side of the finished tree, perhaps just slightly forward of 90 degrees from the front. This can be the first branch on the tree in a medium size composition.
If you have a really strong whorl where there are 6, 7 (I've even seen as many as 15 buds), remove them as soon as they're large enough.
The problem with keeping whorls is that the space between them is pretty large in most cases. The 2-year whorl is a prime candidate to keep because it's only 8-14" above the base. But the 3-year whorl is then 16-24" above the soil and would only be kept for very large bonsai trees. It's typically better to relegate the 3-year whorl to part of the sacrifice branch or remove it as I suggest in the scenario in the article.
If you bend over the third year growth and use the side bud as the next trunk section you'll have a better scenario for internode length moving forward. The dominant central bud will grow out and get to vertical again and the side bud facing up will gain some strength, but it will remain shorter than the main leader. Thin the buds in that the following fall and then start treating it like the top. You would wire it, select another sacrifice after a couple years and then once that branch takes off enough encourage it by reducing the first sacrifice branch.
I received my seedlings bare root this spring. When I got them I put them in nursery pots. Would it be better to leave them those containers to grow another season or should i repot into colanders in the spring?
I guess that depends on the size of the nursery containers, the soil and how your root trimming was done. I feel it's generally better to correct problems sooner rather than later. So if you think your roots are going to be a problem repot at your next opportunity.
I could write a whole other article on how to keep on top of the root development. When you do root work on the 2-year olds you're removing something like 80% of the roots. Then you try to flatten them out and arrange them in the basket such that as they get larger they're not crossing etc.
Inevitably, some roots are crossing and have to be removed. Others look awkward, are slightly too high on the trunk or have some other problem and also have to be removed. The good thing is that if you remove them around year 4-5 then the later fattening of the trunk will heal over the cuts and you'll have a better base for it.
Don't use wire on the young root to anchor the tree in the containers - I use a set of guy wires from the wire wrapped around the trunk to the colander edges so that there is no wire below the surface to cut into the roots as they enlarge.
