Plant out in a sunny spot and incorporate well-rotted manure or garden compost and perhaps some mycorrhizal fungi into the soil when planting. If planting out in a large pot (40cm+ diameter), use a loam-based compost such as John Innes 3 over several inches of drainage layer e.g. gravel.
Keep well-watered during warm weather until the plant has settled in fully, and once the plant has become established, prune it each year in March, cutting all of the previous year's growth back to within two to four buds (15cm or 6in) from the base.