Raised or Blocked Herb Gardens
One way to help guarantee that your herbs are not going to spread and possibly overtake the rest of your garden, is to plant them in a raised garden. First, determine the amount of space that you have available for them and the condition of the dirt in your ground. Coming from Arizona, our soil is not the greatest without massive conditioning and treatment first. Then there is always the recurring problem of ground squirrels.
To reduce or remove these obstacles, make a raised bed garden. It will greatly increase your usable space and because there are bottoms to the beds, ground squirrels cannot get to your roots.
A raised bed is easy to make, use a non-treated wood, as you do not want the chemicals in the wood to seep into your food source. Make the tallest parts of the bed in the back, and use those for the plants that need longer root spaces.
Many herbs, such as mint (all varieties), or cilantro can be invasive, therefore make sure you put them in smaller raised boxes or even along the edges of your garden inside cinder blocks. Not only does that keep them from invading your other space, mint and cilantro both are very good at keeping ants and some other pests out of your garden.
Before planting begins, design the outline of your garden, where the water sources are and where the sun can best be utilized. The preplanned garden is the best garden.