Hostas, or plantain lilies, are popular because they give color and texture to perennial gardens from mid-spring until mid-fall. Large clumps of basal leaves with pronounced veining and smooth or wavy edges distinguish hostas. Leaves come in various shades of green, often with variegations. Lilylike flowers on tall stems (or scapes) in white and lavender bloom from late spring to late summer. Size and shape vary tremendously, with petite types a few inches tall for rock gardens at one end of the scale and giants with a single plant the size of a half whiskey barrel at the other.