Help pruning Laburnum 'Vossi' (Goldenchain)
I planted this tree two years ago and it is growing vigorously, with great flower displays each spring. How should I prune it to encourage vertical growth? UW arboretum has some nice specimens at least 50 feet tall---but I don't know if they are the same variety. Maybe 'Vossi' wants to be more droopy.
Mine is growing out prolifically but doesn't seem to have a dominant leader. I tried staking the biggest branch upright but the whole thing is kind of floppy. How should I approach this? I have room for width but I don't want a shrub.
Here is a link that might be useful: Two photos of my tree