I have a norway spruce in a small garden which is about to be removed. Will other plants grow in the soil or will the drop of needles over several years have contaminated the soil. I know they are acidic.

I'm sure it'll be fine, but I would still add a generous amount of fresh, gritty multi-purpose compost into the hole when planting your cordyline to freshen things up a little.

'Norway spruce' - Not sure about the needles but I sure wish you were close to my house so I could take the Norway spruce....! I'm looking for tall stuff to plant as screening at our back fence. Pity!