I am always happy to collaborate with your florist when it comes to flowers for your cake, its always nice when everything matches! I prefer the flowers to be delivered to me the day prior so that I can tape and wire them correctly the morning of the event and attach them to the cake prior to delivery to the venue. Alternatively I also have a wonderful local florist and can usually match flowers easily.  Some florists like to put the flowers onto the cake themselves which is also ok so long as the flowers are taped prior to being attached to the cake