That is, they display indeterminate growth or, at least, their stems and roots do. When left untouched and growing in an unrestricted volume of soil, a plant’s roots will never reach an established size, nor will its branches in the freedom of an open-air space. Limits of plant growth are proportional to the availability of light, water, minerals, and oxygen. Life span is genetically determined—one year for annuals, two for biennials, and indefinitely for perennials.
