How do plants grow?
Special cells in plants produce hormones, chemical messengers that tell different plant cells to perform certain activities. Plant hormones are responsible for things like fruit development, the death of flower petals and leaves, and, most importantly, for growth. Cells in stem tips, new leaves, and buds, for instance, produce various growth hormones that tell plant cells to multiply by division or to become larger. The pattern of growth in plants is an important example of how they differ from animals. While animals eventually become fully grown (and live for a long time after that point), plants never stop growing throughout their life cycles. In other words, there is no such thing as an adult plant that no longer grows but continues to live.