Kentucky Colonel Mint This page first published: Apr 27, 2005 · Updated: Jun 14, 2018 · by CooksInfo. Copyright © 2021 · This post may contain affiliate links · This blog generates income via ads · Kentucky Colonel is a hybrid spearmint that has large, dark green leaves with slightly crinkly surfaces.It grows up to 2 to 3 feet (60 to 100 cm) tall and can spread out over a yard (1 metre.) It blossoms with purple flowers during the summer.