The South African groundcover known as bacopa is botanically Sutera cordata (ht 20-30 cm, spread to 40 cm). It has simple, rounded flowers and comes in various colours in single and double forms. Cultivars include 'Snowflake', 'Gulliver Snow', 'Double Pink Pearl' and 'Great Purple'. They bloom for many months, beginning in spring, and seem very tolerant of a hot, sunny position, though can apparently also grow in part-shade. They seem to be excellent plants for creating a soft and flowery effect, especially for cascading over walls. Propagation is by detaching rooted pieces and potting them on. In my experience, the plants don't last a long time and should be started anew each year.