Some plants are edible only in certain stages of growth. Some examples are: Bracken fern is not edible after the fiddle head stage. Nettles can cause kidney problems in some people if they are mature (seed growing on the stalk). Yucca stalk (Hesperoyucca whipplei ) gets too many bitter saponins to be palatable as it matures into a flower head. '''Be careful.'''
