Kisenian flower is a flower that can't do anything on its own. It takes control of a weak willed individual and makes that person do what it wants. The Kisenian flower took over Fiore and told him to destroy earth for what the humans had done to Mamoru.
Sailor Moon R: The Movie. During a visit to the park, Mamoru, Usagi, Ami, Rei, Makoto, Minako, and Chibi-Usa are enjoying a summer's day. However, their day of fun and enjoyment suddenly comes to an end when Fiore comes down to Earth to return a favour to Mamoru. However, he is jealous that Mamoru has a girlfriend (namely Usagi), and Fiore feels somewhat betrayed. This misunderstanding leads to the Kisenian flower turning Fiore against Mamoru and all the citizens of Earth. When he launches an attack with evil and deadly flowers, the Sailor Senshi attempt to save Earth from the take-over by the Kisenian flower. As the battle rages we learn how very important Sailor Moon really is to all the Senshi. Foire is freed from the Kisenian after he learns that even he was touched by Sailor Moon's love.