They generally grow to about 1m tall and with a spread of about 0.5m. Don't plant them too deep - I would plant them so that the top of the roots are about 5 cms below the soil surface.
I wonder if that means my order, with the 6 free phlox paniculatas are going to turn up soon too?

These are a lovely old fashioned cottage garden plant. It can help sometimes to pot them up for a few weeks to get the root system going. They will thrive in sun or semi shade and need dividing every 4 years or so to maintain vigour. I wish I had some plants coming!!

Volunteer, Have a look at the J.T.Parkers website - they may still have the offer on.

They prefer damp soil too.