You can simply chant “Come Flowermaker” to get his attention, but in Theocraese the mantra is “Veni, Veni, Veni Agarachandax.” Agarachandax is a Theocraese word meaning maker of flowers, but has connotations relating to the god himself such as being a psychonaut, an artisan, or transgender. Some people may have more success calling him Aga Champa or other channeled names, which all mean the same thing.
Poppy seeds are the best thing to have around in order to evoke him. Planting poppies or other psychoactive plants are good ways to strengthen his energy. Even for those who cannot see him, his energies will raise the vibrations of the chanter and guide them towards worldly hedonistic pleasures if not just granting them to a person throughout their day.