All diascias need a well drained soil and warm situations, (they all hail from South Africa), such as the base of a south or west facing wall. Flowers are in the pink-apricot range, but with some new forms introducing a dusky blue-purple. If the foliage becomes untidy, give them a good cut back and it should encourage more blooms.
In their native South Africa Diascia species have a very specific relationship with one small genus of bees as pollinators. However in our gardens a range of generalist species such as honeybees and hoverflies are able to make use of the nectar and pollen.