I’ve had this alder for 12 years and it’s been a royal pain in the ass!! You just start to get it into shape and it starts dropping branches. I was on the verge of getting shot when I decided to give it a little extra room to grow last year. This seemed to work well with plenty of new growth. I took the bull by the horns and gave it a hard pruning to force some more inner branch work to develope. This also worked. I repotted it this Spring into a larger pot than previous ones and this time I have added some bark to the mix. I feel that the usual mix of SC Cat Litter and grit isn’t ideal for this variety, not enough water retention. The bark seems to be making a difference and the tree is growing strongly, probably stronger than usual.
It’s a tad unkempt as I am waiting for further growth before shaping. I had to do a little work on the deadwood area where die back had occurred on the trunk.