I live in zone 8a. This plant is listed to prefer zones 3 to 7b but I have a spot and will try it there.
Just wanted to put that out there. I know its just a guide and success really depends on many factors.

My research tells me 4-5 feet in width and 4-5 feet in height approximately at maturity.
Also it blooms on old wood. If it survives my zone I will train it to be 3-4 feet in height. New growth will still appear but i would cut it off in the fall to maintain my plan. Will this species survive yearly cut backs? Will blooms return every year on the old wood maintained at 3-4 feet?

Soil tilled and fertilized
Feed I use Cottage Farms bud n flower booster

The answers to all your questions are 'No'. Zone 8 is too hot for this plant. Pruning every fall will cut off the old wood because the old wood is the wood grown during the summer after it blooms.

This particular Sambucus is not very hardy to begin with. You might want to invest in a plant that will be happier in your zone and will maintain the height and width you want.

Thanks Daisyl.
Haha I really bombed out on that one.
As you can see my knowledge is limited. Your explanation of old wood furthers my quest!

How much will you take for it?

quercusnut I do not have this plant. I was inquiring about it before i bought it.

Ahhhhh......