Lucky you, Pierre de Ronsard is a lovely rose. I was given one and it did so well in my East Leicestershire garden- but did not survive the move here (unlike other David Austin roses that did). Do you know where it was bought? I would ask the suppliers for advice. Personally I would plant it in a large pot- but make sure you mix soil and not use only compost. Is it a bare root plant or in a pot?
The rose expert for Romandie is not far from you- why not go and ask him. Alain Tschanz has tons of experience and is very friendly.

http://www.rosiers.ch/