Do hallucinogen mushrooms grow in Iowa?

They are illegal no matter the state.

Psilocybin and Psilocin are Schedule I drugs which means that the acuall mushroom that has been grown to at least the mycelium stage is illegal, in some states the act of inoculating a jar with spores of a psilocybin and psilocin containing mushroom is illegal as long as the grower knew before hand the the spores came from a mushroom containing psilocybin and psilocin. these laws can be very tricky because they have to prove the prior knowledge.