Ginseng Life History
Ginseng begins life as a seed, dispersed inside the berry in fall, and remains in the soil through through at least two winters (sometimes 3, 4 or 5) prior to germination in spring. Ginseng may remain a 1 leaf plant for several years as it accumulates enough stored reserves to grow into a 2 leaf, adolescent ginseng. A 2 leaf ginseng plant may develop flowers and seeds, but reproduction is intermittent and low. Ginseng remains in this 2 leaf stage for another 3-5 years before developing into a large adult plant (typically with 3 leaves), which may in old age eventually have 4, or rarely 5 leaves.1 These large adult plants are the primary targets of harvest. Note how slowly ginseng grows compared with plants in cultivation.
Defining these life stages is important for demographic research. As you can see, plants at different life stages vary in terms of seed production and mortality. In order to accurately model population growth in American ginseng, life stages that capture these demographic characteristics must be created. This type of classification is referred to as stage-based classification, because we use the size or stage of the plant, not the age, to assign ginseng to groups. Finally, we incorporate an age-based model of the progression of seeds through the seed bank. Seeds can remain viable in the soil for up to four years.
The analogy with human development only goes so far. In fact, unlike humans, ginseng plants can revert to earlier stages, reflecting a 'plastic' response to the environment. After being browsed by a deer, or experiencing a bad drought, a given plant often comes back the next year reduced in size, lower in reproductive output, and potentially more likely to die.
Within a year, ginseng plants stay in a particular stage. This does not mean they are passive and unchanging with the passing of seasons, however. Here is an amazing time-lapse sequence showing a single plant as it emerges in spring, flowers in summer, then senesces in fall while the environment changes dramatically around it. Watch a time-lapse video of a Year in the Life of a Ginseng Plant- 2013
References:1McGraw et al. 2013 (review paper)