Plant in full sun in well-drained soil with good air circulation. If you have clay soil, add sand and organic matter to lighten the soil and provide better drainage. Plants will get leggy or flop in too much shade.
When the young plants are growing freely, pinch or trim off the branch ends or tops to encourage the plants to branch out.
Prune established plants back in the early spring every year, cutting out the oldest growth to promote new growth. After 3-5 years, if the plants get woody and stop producing lots of branches, the plants should be dug up and replaced with new ones.