Is jimsonweed the same as moonflower?

Yes, jimsonweed is the same as moonflower.

Specifically, the two names are common names for one plant which carries the scientific name Datura stramonium. Other common names include angel's Trumpet, devil's weed, Jamestown weed, jimson weed, stinkweed, thorn Apple, and tolguacha. All of the names refer to a plant that matures to 2-5 feet (60-150 centimeters) in height and showcases leaves whose uppersides are darker than their undersides and whose trumpet-shaped flowers range from creamy to violet to white.