I don't know , all I know is ,we were ridding along on a mountain in VA. where I used to live , Haysi VA . , And I saw these growing next to the road , well I got them , and took them home planted them, and when I moved to Mich . I brought them with me, that has been 8 years ago . these get bigger ever year , and you can have them as just one tall flower , or you can have as a bush , just one bush has 100's of seeds . thank - for your Question . thank-you for looking .