Tall stuff in the back yard

I've mentioned before that Dad and I like to grow stuff. Doesn't have to be important .... just fun to help things grow. This year Dad got a pretty tall hollyhock that sort of sneaked into the edge of the watered area of the garden, and he has a gladiolus that is also taller than he is. Dad is not short by the way! Also a mysterious plant "volunteered" in the flower bed, and like usual, Dad didn't have the heart to just pull it up..... "I think I'll wait and see what it is? Looks like corn?" Now that it is bigger, we're pretty sure it is some variety of sorghum - probably left over from the winter's birdseed?