All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His Slave and Messenger.
The presumption is that nothing in Sharee'ah prohibits offering a flower bouquet as a gift, be it big or small. A gift is not necessarily intended to be for material benefit; rather, it is an expression of love and affection on part of the giver.
Allaah Knows best.