Variegated tapioca would be a showstopper in any garden with its fantastic foliage. See more fun plants: www.bhg.com/gardening/arboretums/allen-armitage-plants-university-of-georgia/?socsrc=bhgpin070312
Castor Bean While it's technically a perennial in the tropics, most folks grow castor bean as a fast-growing annual. This heat-loving plant can reach more than 15 feet tall in a single season. Be wary, though -- all parts of the castor bean plant are very poisonous. Zone: 10...so it is an annual in our zone 4.