Half Hardy Annual.
Sow seeds in February /March in pots or trays of seed compost and propagate @16C.
Prick out seedlings when large enough to handle into 70mm pots. Harden off in a coldframe before planting out in May(or when all fear of late frost is past)
These plants do not require a rich soil,in fact if too rich you may get a lot of leaf growth at the expense of flowers.
Deadhead regulary to give continuity to flowering period.
This variety has the fragrance of chocolate, hence the name! There are other varieties with white pink or red flowers.