On the farm, sometimes, weeds will sprout out of cow patties. They are called "shitweeds". The term is also used for a person who is miserably disagreeable, an asshole or a jerk, but has a greater depth of meaning. It represents someone who is bad and worthless (like a weed) who was spawned by something equally worthless (like shit). A person who is a "shitweed" is similar to white trash, a low and base person raised by low and base people.
Aubre Shitwell is a very kind and funny person that could light up a whole room with one smile. She is the mother of her group of friends and your mother might ask you "why cant you be more like Aubre?". She'll love you unconditionally and stand up for your ideas even though they might be hella stupid. she will tell you when your're wrong and maybe even tell you to eat her ass.