Wiktionary
anthophobia
n. fear of flowers.
Wikipedia
Anthophobia
Anthophobia is an abnormal and persistent fear of flowers. The term comes from the Greek roots anthos, flower, and phobos, fear.
Though sufferers generally understand that they face no threat from flowers, they invariably experience anxiety at the sight or thought of them. Any genus or species of flowers can instill fear, as can any flower part, such as a petal or stem.