Rosemary bushes can live for up to 15 years. They make a great addition to any garden and can be shaped into topiary. They also can grow to be quite large, so in addition to your usual snipping for culinary and crafting purposes, you may need to occasionally prune your rosemary bush to control its growth. Prune your rosemary in early spring or late autumn.
Clip the soft, new growth from the rosemary plant to use for cooking and to dry. You will want to wait at least two weeks before cutting any sprigs after pruning.
Cut any straggling stems. These will be the larger stems that are growing beyond the main bulk of the bush.
Start at the bottom of the bush and clip no more than 10 to 12.5 cm (4 to 5 inches) from the tips of the stems. This is for a full-grown rosemary bush. For young rosemary bushes, clip no more than 5 to 7.5 cm (2 to 3 inches).
Work your way around the bottom of the bush. Clip so that the bottom fourth of the bush is even all the way around.
Move upward around the bush, clipping back slightly more than you did around the bottom as you go. Do not clip too much though; the overall difference between the top and bottom of the bush should amount to no more than 7.5 cm (3 inches). This will shape your rosemary bush, giving it a uniform look.
Check for stragglers and clip those. Now that you have the shape of the bush, you can determine whether you should prune back any farther.
Prune back farther if the outer stems are still quite soft and you don't need to cut any more clipping for at least a month. Prune back only 2.5 to 5 cm (1 to 2 inches) at a time so you don't cut into the thick, woody portions of the stems.
Continue to clip soft, new stems as they grow. This practice will reduce the need to severely prune your rosemary and still maintain a pleasing shape.