Rosemary plants (Rosemarinus officinalis) can be divided into two basic types: prostrate and erect. Creeping prostrate plants spread along the ground with a maximum height of 2 feet, unlike upright forms that can grow up to 6 feet tall. Grown in U.S. Department of Agriculture plant hardiness zones 8 through 10, common prostrate cultivars include "Prostratus," "Lockwood de Forest" and "Renzels." Prostrate varieties do well as ground cover in rock gardens where they creep across rocks. Special care must be taken when transplanting to avoid damaging the foliage on the ground. Spring is the best time to transplant rosemary.
Prune back extra-long rosemary stems to make them a more manageable length for transplanting. Some prostrate varieties spread up to 8 feet wide, but rosemary takes well to hard pruning, so you can cut them to only about 2 feet long. Prune the rosemary in late winter before new growth begins.
Lift the branches off the ground and gather them in a bundle. Tie the branches with soft twine or fabric strips to hold them off the ground so you can dig.
Cut a 12- to 18-inch-diameter circle around the base of the prostrate rosemary, using a digging spade to dig to 8 to 12 inches deep. Cut a second circle about 4 inches out from the first circle and remove the soil between the two circles to make a 4-inch wide trench. This action severs the longer roots, signaling the plant to grow a dense network of short roots within the 12-to 18-inch circle before digging up and moving the plant in spring.
Remove the twine after digging to reduce strain on the branches.
Water the rosemary plant deeply on the night before digging up and moving it. This softens the soil, making it easier to dig, and ensures the rosemary is well hydrated to reduce transplant shock. Bundle and tie the branches off the ground so you can access the plant base.
Clear all vegetation and loosen the soil to a depth of about 12 inches in the new planting site. Rosemary needs a site in full-sun that receives six or more hours of direct sun daily. Rosemary tolerates poor soil and rocky soil, but you can add organic amendments, such as aged compost and manure, to build structure and add nutrients. Heavy clay soils benefit from the addition of 4 to 6 inches of organic matter, in addition to coarse sand to improve drainage.
Insert a round point shovel blade into the 4-inch trench around the rosemary plant. Push the blade under the plant and pull back on the handle to pry the roots. Reposition the shovel at different points around the rosemary and pry up the roots until you can remove the plant from the ground. Set the rosemary on a tarp or bag and wrap the roots with a damp towel until you get it planted.
Dig a hole in the new planting site that measures two to three times the diameter and the same depth as the transplant root ball. If the root ball measures 12 inches across and 8 inches deep, dig the hole 24 to 36 inches wide and 8 inches deep. Set the soil aside and mix in about 1 tablespoon of a slow-release, all-purpose fertilizer, such as 10-10-10.
Set the prostrate rosemary plant in the planting hole so the top of the root ball rests at the same level as the surrounding soil grade. Back-fill the hole and pack the soil gently with your hands to remove air pockets.
Spread a 3- to 4-inch layer of bark chip mulch over the soil around the plant, but do not push the mulch directly against the plant stems. Untie the twine and spread the branches evenly across the ground.
Water the soil around the plant until it is evenly moist. Water about once weekly for the first few months until the rosemary becomes established and begins to grow. Established plants are drought-tolerant and only require watering during long periods without rain.