My next door neighbor has a tree service. In the past he dumped wood chips at the back of his property to fill in a low area. About 3 years ago a small group of plants popped up in the chips. I could see that they were Castor plants (Ricinus communius).This is how they look now.
These plants are 15 - 18 feet tall! They have spread across the width of his property. Its too bad they are toxic.
