How to Transplant a Rosemary Bush

Rosemary (Rosmarinus officinalis, USDA plant hardiness zones 7-11) lends a distinctive flavor to chicken, potatoes, fish and many other foods, and it's a delight to grow. If you live in its hardiness zones, you can grow a rosemary bush outside as a perennial shrub, but in colder areas, it's best to keep it in a pot and bring it inside during the winter. You can also start one in a pot, and once it starts flourishing, you can transplant it into your garden.

Rosemary plants in pots do well when you give them well-draining potting soil and a container with drainage holes and a drainage pan. Interestingly, they are known as an "upside-down plant." This nickname is because they absorb moisture in the air through their foliage, and the roots stay drier. This dryness means that you must add a layer of small rocks or gravel to your drainage pan; the pot has to sit on top of these instead of right in the pan. Keep the container in full sun; a bright, sunny window is best.

Water the plant every two weeks and keep water in the pan (with the rocks). This way, your rosemary can benefit from the water that evaporates into the air. You can also mist it with water once or twice a week if it seems thirsty. A rosemary pot only allows the plant to get as big as the container's size, and if the roots are left unattended, they will take over the whole thing. The plant won't be able to absorb water or nutrients, the foliage will stop thriving and the plant will probably die.

Transplanting a rosemary bush to a larger pot is pretty simple. You'll need a larger pot that provides 1 inch or more in between the root ball and its sides along with fresh potting soil and a pair of clean, sterilized garden shears. Carefully lift the whole plant out of its container and place it on a level surface. Gently trim off about 2 inches of root matter from the sides and bottom, adding two to three vertical cuts on the bottom of the root ball.

Now, you're ready for the finishing touches. Start by adding soil to the new container. Then, you can put the rosemary in the pot and fill it in with more soil. Some recommend adding a third of builder's sand or perlite to the dirt; you can also opt for an organic succulent or cactus soil. Water the transplanted rosemary bush thoroughly and keep it in the shade for a few days.

Rosemary bushes should be planted in full sun outdoors with well-draining soil; choose a spot that gets six hours or more of sun per day. They also need enough room to grow because they can spread up to 4 feet tall and 4 feet wide. Good companion plants include other herbs, like sage, plus vegetables, like carrots, cabbage and beans. You can prepare the soil by adding 4 inches of compost to the surface and working it down about 6 inches.

Dig a hole that's slightly larger than the root ball and gently remove the rosemary bush from its soon to be former home. Check the roots and trim off any dead or decaying parts. You can also trim it. Lower the root ball into the hole and then fill in the dirt. Now, you can give it a good watering but be sure not to flood the roots.