Report Abuse. Depends on the species and variety as to how big a hibiscus plant will grow. Your local soil and climate will also be a determining factor in this as well.Most tropical (woody) types average 6-15 feet tall and the hardy or perennial species range from 3-12 feet in my experience.eport Abuse. Depends on the species and variety as to how big a hibiscus plant will grow. Your local soil and climate will also be a determining factor in this as well.