Most evergreens are poisonous so that is your first consideration if using a real cake,Hypericum berries too , even if not ingested many people get a rash from them.
If the cake is a dummy that's different, they can be simply inserted between the spacers or wired into a long garland which will give you a little flexibility for arrangement.
I personally would use some of the excellent silk foliage and berries available especially if the cake is a dummy...they'll last forever.
Sorry, forgot to add that I think I can spot pillars through the foliage.
Thank you :) Yes, I was wondering how those pillars are constructed into the cake? I use SPS sometimes, but can also use Wilton separators (I think I'd seen that at Michaels).. any advice on that?
Didn't know that evergreens can be poisonous!! Thanks for letting me know!!