I have a wedding cake coming up, and she wants it decorated with fresh roses. Anyone have suggestions as to how I should prepare/ wrap the rose stems so that I can safely stick them into the cake?

Hi Karis,
When I have used real fresh flowers I used the plastic flower picks you can buy from many of the cake decorating sites. Either that or you can wrap them in florist tape and dip them in chocolate. But I think it's safer to use the picks and the flowers stay fresher. And they don't leave large holes in the cakes.
I will go and look at a few decorating sites and see where they are, be back soon.

Wildrose

I'm back I think I must be tired I have seen them before but:
I did find them at Golda's Kitchen and they were called cake spikes also they have the cake topper that you fill with water and place the fresh flowers in an place on the cake.
Global Sugar art has some under flower accessories. I have seen them at Kitchen Krafts before. And Sugar crafts

I hope that is good for a starter I'm sure others will think of some other places

Go have a look
Wildrose

I'll check those out, Thanks!