Alcathaea Suffrutescens Parkallee This tall perennial has been developed by crossing a common hollyhock (Alcea spp.) with an Althaea. The goal was to produce a plant which put on a prolific dispaly of flowers, but didn't suffer from rust like a hollyhock. After many years of development, this is the result. Unlike the more upright hollyhock, it will quickly form a spreading vase shape, and its stems will be evenly studded with open bowl-shaped flowers from July to November.