it looks like a datura stramonium, common names are thorn apple or jimson weed, related to angel trumpets. Be careful if you have small children or pets, it is a poisonous plant.

Oenothera species? Here is a link that might be useful: Oenothera glazioviana

its a perennial... and can generate horseradish sized roots... which will be hard to kill ... the poisonous deep purple berries are an attractant to kids who like to stick things in their mouths... use the G W search for thousands of posts about such ... kill it now.. or you will spend the next decade pulling seedlings out of your garden ... and try to dig up the root.. all of it.. or drip round up on the cut stalk ... ken

There's several datura varieties that are quite beautiful and widely grown, especially the Metels. Unless you have especially sensitive skin you shouldn't have any problems from just touching the plant. Just make sure you don't rub your eyes after touching it in case you have sap on your fingers. Here is a link that might be useful: daturas