How to spread African marigolds

African marigold (Tagetes erecta) is the tallest marigold of the group, which includes Scotch, French and triploid. The plant can get up to 36 inches tall and primarily comes in golden or orange but may also be mahogany. Blooms may be 1/2 to 4 inches across and produce for some months if deadheaded. African marigold is heat tolerant once established.