i doubt you would ever dig it out ... hacking off so many roots.. it would ever survive ...

just get rid of it ...

cut flush the ground.. and use a stump killer ...

unless you bonsai it.. which involves taking it out of the media and root pruning it once or twice a year... you arent going to dwarf a monster with a small pot ...

ken

You probably have the variety 'Compacta', which is not a dwarf and not even very compact :-)) 10' or more is standard for this selection, compared to 15-18' for a standard burning bush shrub. There ARE dwarfs -- 'Fire Ball' gets to only about 5' and 'Rudy Haag' is only about 3-5'.

Either of those would be better choices for container growth than attempting to transplant a large plant from in the ground.

And depending on where you live, these dwarf varieties may be diificult to locate. Burning bush is invasive in many areas and in some states, sales are restricted.

And BTW, invasive doesn't mean a plant you thought would be small has gotten big. Invasive means it escapes into the wild, the natural environment.

If you cut it back entirely, it will grow back and be smaller.....for a while. Whenever my "dwarf" gets too big for my liking, I cut it down to about 1-2'. Does not take long to fill back in. You may be able to prune off some of the outer branches and keep them continually pruned back to keep the width in check, but I think you'd always be fighting that battle if it's too wide for the space. I'm fortunate in that I just prefer it to be shorter. If you're going for shorter and narrower, it might be a lost cause or at the very least a lot of pruning.

Have maintained my 'Compacta' in a pot, for several years. It is about 3 feet by 3.5 feet. Certainly would suffer, without attention to adequate watering.

I cut a 'Compactus' on a property I work down quite low each winter or spring that it is needed to keep it from blocking a drive. If you cut it off quite short the re-growth looks normal, the stumps being only down near the ground. Comes back well enough each time to be ~presentable the first summer afterward, takes about 2-3 years I guess to get "too big" again.