Posted: 06/09/2016 at 14:28
I t won't seed if it's kept clipped against a fence, It doesn't flower til it gets to the billowing out stage. Cut off any that starts changing the shape of its leaves to the mature growth shape.
Unlikely to get out of control in a pot, stop watering it in summer, that'll stop it dead.
There is nothing that grows and does exactly what you want without a little attention now and again.