I would like to transplant a young snowball bush, when is the best time to do this. It is currently January and it is just beginning to bud?
viburnum opulos (roseum)
Generally the best time to move things is when they are asleep/dormant, but the ground is not frozen. I'm not sure how cold it gets there. If you are getting buds I would think it is close to how it is here. If you need to move it now, you can, just make sure you get all the roots and don't cut off any and be careful not to beat it up too much and you should be fine. What you want to avoid is moving something when it is too hot. When things are in bud you will always run the risk of losing the flowers, but shrubs are pretty tough. Good luck!
Just be sure when you transplant anything to give PLENTY of water for the first few weeks!
I would think that the sooner you move it now the better.
Those buds may stay dormant a bit longer. And of course, Eco is right get as many roots as you can.
dig out away from the plant about as tall as it is and get them out gently. the feeder roots will tend to run to the side further than you'd think as well as down. It won't be as deeply rooted as you'd think... I've managed to rescue a few plants since I learned this secret.
When you replant your shrub, it is a good idea to use a soluable fertilizer with a high phosphorous content (the middle number) as P promotes good root developement. Also a product with IBA ( indolbuteric acid) a rooting hormone.