It is distinguished from a shrub by its ground-hugging stems and lower height , with overwintering perennial woody growth typically less than NUMBER@1 NUMBER@2 cm tall , or by being only weakly woody and/or persisting only for a few years .

Gardeners use the word to distinguished plants from a shrub that have lower height , typically less than NUMBER@1 NUMBER@2 cm tall , or that are only weakly woody and/or persist only for a few years .
