I wanted to use gypsophila on a naked cake for a birthday this coming weekend. I googled it and its toxic and even the buttercream that comes in contact with the flower can be dangerous if eaten. Google 20 Poisonous Flowers To Look Out For from Pro Flowers.
I've been researching the use of fresh flowers on cakes and it seems like as long as there is a barrier (ie. florist tape and straws) between the flowers and cake they can be used? Would love to get more information from the experienced cakers on here who use fresh flowers.
https://www.cakecentral.com/forum/t/850356/for-those-who-use-fresh-flowers-on-cake this thread is going on right now as a matter of fact