You don't, if you mean Alcea rosea - why do you think you do have to? And if you can find that much peat anywhere, I'd like to know where from - it's as rare as hen's teeth these days...

You don't have to plant anything in peat. A 'peat free' compost is neutral enough for all plants.

Is he or she maybe talking about peat pots or pellets? Sometimes that's recommended to reduce root disturbance when planting out.