Do you mean true Valerian, Valerian officinalis, the herb with the root that drives cats wild and the scented pink and white flowers, or the commonly called 'valerian' Centranthus ruber, with its bright red flowers?
Both are perennials and grow in reasonable soil anywhere. Once established it is difficult to get rid of either.
Centranthus is a Mediterranean plant though, and tolerates very alkaline conditions, but it likes well drained rocky soil. True Valerian will do best in a deep fertile soil. It's worth growing just to watch the neighbourhood cats making fools of themselves if you damage the root to get the odour to attract them! The root is also the source of a VERY powerful 'natural' tranquilliser or sedative, but I would not recommend using it this way without professional advice.

I've lots of Valerian centranthus ruber growing in my garden, red, White and pink. It loves the sun, though I still have some happy in shade, is happy by the dry stone wall, is drought tolerant, but looks very healthy with all this rain. In all, it's a survivor, often found in Coastal areas with sandy, free draining poor soil. Set seeds spring or autumn...best thing to do is get someone to give you a piece, then you'll find new seedlings growing all around it the following spring.

thank u im gonna have a go, ive always liked them but not sure how or when but ur advice has helped.

ps ive got a cat who is pretty daft now so should be comical to watch him..lol.