Did a gardener grow that flower or did the flower grow itself? Well, the gardener cultivated that plant. He facilitated its growth by sowing the seed, providing good compost and other growing conditions and keeping pests and diseases at bay. But the cell elongation and division, the differentiation and the enlargement were done by the plant, with the aid of suitable conditions of light, moisture, temperature and nutrients. Growth means a specific thing to a biologist. Not quite same thing as cultivation. Generally speaking, plants manage fairly well without too much human intervention. That gardener was indulging in a little bit of artificial selection.