Any geographical region will generally have a number of planting regions. The United States includes areas that have very heavy rainfall and tropical conditions as well as arid areas with cold winters.
A regional planting guide can be used to make plant choices, including trees, shrubs and vegetables. In areas with hot summers, a guide might suggest tomatoes or peppers, whereas in mountainous states such as Montana and Wyoming with cooler summers, a different group of vegetables may be suggested.
A guide indicates the correct planting times for your region and when to conduct landscaping tasks, such as pruning. Some online guides can direct the user by zip code when searching for the right planting region. Since many areas have microclimates, a small region can have several different hardiness zones.