A few months ago, when I went to my future job (primary school), I was offered a few Tagetes plants that were left alone at school for the holidays and I decided to give them a home. They were already in a very poor state and my absence, dessication and then brutal summer rains did not help them at all. However, they did grow some nice flowers, even though the leaves look very very sad.
Autumn weather dried the flowers and developed seeds. Maybe next year, when I let them sprout and grow, their offspring will have more favourable conditions and will grow into big and healthy plants.