Rosemary Rex Ultimate Size

I live in Coastal North Carolina, USA and purchased a tray of rosemary Rex in 2000. As the name implies this variety is growing large, with the longer branches now reaching 4' long. It grew so fast that I had (have) to dig up the ones I had planted near the house and transplant them further away. My question is, how large does this grow. I want to, when I transplant (soon), place them in a spot where they will have plenty of room to grow to their maximum capacity.

According to Hortus, Rosmarinus officinalis grows two to four feet (60 to 120 centimeters) tall with the occasional plant reaching six feet (two meters) in height. Since coastal southern USA has the ideal climate for the species, the Rex variety might even grow a little taller than this. However, remember that you can always prune the plant to whatever shape or size you wish. The Rex variety would never have become a valued commercial variety, if it reacted badly to trimming.