Hi christie_sw_mo,

Elderberry have a somewhat shallow root system, however the roots are fragile, so care must be taken when digging them up. Your plant is young and so the root system will not be extensive and not so fragile. I would transplant now getting as much of the rootball as possible. Water it in until freeze-up and kept watered though the spring early summer.

Ian

I think it's doesn't matter when to transplant sambucus, I've done that in a spring, summer and a fall, but my choice will be the early spring while still dormant since at that time you basicly could treat it as a bare root plant and not worry too much about getting large chunk of soil with roots.
For the 1 year old plant you might have a substantial die back in a first winter, maybe even completely killed top growth, but don't worry.
Worse come to worse it will grow back from the roots.
As Ian said, root system is shallow, but rather wide, so dig accordinghly.

I'm more confident about transplanting in early spring since that's what I've done the most with other trees and shrubs but this thing was growing so fast, I'm considering moving it now in the fall before the roots have a chance to grow more. Would the roots grow more over winter? We've had a couple freezes with temps in the mid twenties but our 10 day forecast is above freezing. Did I wait too late for fall transplanting?

I'd say you can transplant now with no problems at all. Freezes and frosts won't matter.

I moved (4) 8-10' tall 3 year old plants last summer. All did well. Three took off and 1 initially suffered a setback before responding. They are quite shallow rooted. I dug a rootball that was about 2.5' wide and 1 ft deep. It weighed a LOT. The one that suffered did so because I dropped the plant over a fence moving it. Those that I was able to lift and set carefully in their holes kept right on chugging.

Thank you Kurt - That's very encouraging.

If you need a little more encouragement, you would have to try pretty hard to kill it! It might sulk if you don't get enough root but it will live. I recently removed one (there were some roots going deep, as there are with almost any temperate tree or it would blow over, but this was an old 15'+ tree) and some of the main branches and the trunk continued to grow for months without any roots at all!