Timing of pruning for backbudding?

[James W.]

I have several kinds of trees developing from nursery stock that have long branches with most of the foliage towards the ends. What would be the best time of year to prune them to encourage backbudding and interior growth? At this point I am less concerned with ramification and refinement than with chasing branches back toward the trunk. I know that for conifers in general I need to leave enough foliage to keep the branch alive and not prune past buds and some trees just will not back bud on old wood.
Shortening branches in July and August seems to work well for junipers.
Deciduous trees I have been doing heavy pruning before bud break in the spring.
For mugos I try to follow Vance Wood's wisdom Compiled Posts by Vance Wood on Mugo Pines
I have found lots of good info for Japanese Black Pines and I refer to my books often.
What about spruce? I have Colorado, Serbian, Black Hills and dwarf Alberta spruces but have found very little specific information.
And I am at a loss for my Atlas cedars.

TIA

 

[Colorado]

Personally I think the best time to prune spruce is in the spring before the buds open.

However, I have also worked on spruce in the summer after the new growth hardens off (formation of the central stem on new growth) and have had good results with that as well.

I don’t really like to prune spruce too late in the fall due to my climate and harsh winters.

 

[WNC Bonsai]

I prune spruce 2 times. First i the spri g when the new buds have extended about 1/2-1” I pinch them back about 1/3-1/2 their length. I vary this of course depending on the strength of the branch. This is done for 2 main reasons, (1) to balance strength, and (2) to encourage back budding. Left to their own devices you may only get a terminal bud but if pinched back you may get several back buds along that branch. I do my actual pruning in late summer, around August in my area. This is also a good time to wire branches. Generally after this pruning you will get a lot of back buds even on older wood.

 

[James W.]

Just did a search on this forum for blue spruce, there is a LOT of good information available. I think that most other spruces should be similar.

 

[bwaynef]

I have very little experience with spruce so I hesitate to give any suggestions, but if it is BACKBUDDING that you want, let the tree grow until you see a bud before you cut back to it (leaving foliage on the branch ...which might mean you have to prune it a couple of times until you can coax the bud into opening before you can finally cut back to it.)

Like I said, I don't have much experience w/ spruce. (I've learned the hard way about repotting them too quickly though. I'd advise against that.) The few that I have tend to do well when cutting back to a bud, and rampant growth seems the best way to get them to set buds.

 

[0soyoung]

What @Cofga said ^. I would only differ about spring pinching. IMHO, timid just a means of limiting the length of new growth. Prune to a bud or node now, like he said, for back budding.

 

[WNC Bonsai]

What @Cofga said ^. I would only differ about spring pinching. IMHO, timid just a means of limiting the length of new growth. Prune to a bud or node now, like he said, for back budding.

On his website (Bonsai4Me) Harry Harrington recommends the spring pruning technique so I gave it a try and it does work. He also says that with proper timing on strong trees you can actually induce 2 flushes of growth instead of just one. I must admit that my CBS put out a bunch of new buds after the spring pinching but has not so far made a second flush of them. I believe it was a result of late cold springs which delayed bud break and set everything else back. Here’s a link to his discussion of this technique.

Picea/ Spruce Bonsai – Bonsai4Me

www.bonsai4me.com