Most agapanthus are drought tolerant and are a good choice for coastal areas, coping well with wind and salty air 
Plant in a well-drained soil which has plenty of sun 
Be patient as it may take 2-3 years for the plants to establish before flowering takes off 
Mulch in autumn or cover during cold spells to protect the young shoots 
If the clumps become too big, lift them and split every 4-5 years 
If you are planting your agapanthus in a pot, move to a sheltered position during the winter period, so that the roots are protected from frost 
Plants will flower well in pots if the roots are constricted. They should be split and replanted in fresh compost if the roots become congested, otherwise flowering may suffer