Big'un, No real secret. It is in its 3rd growing season now and is kinda out of control. I am probably going to have to relocate it to a in ground location rather than my raised planter this fall and replace it with a couple smaller ones for the herb garden. The real reason its growing great is probably that since I got married I havnt cut much off it at all bc my wife does not like rosemary. Also it gets watered 30 minutes every morning and fresh mulch around it yearly.