The rosemary bonsai is a fragrant, long-lived perennial. It is a semi-woody tree that can tolerate short periods of drought. The rosemary bonsai is resistant to pests and often is cultivated as an herb. The rosemary bonsai's hardy characteristics make it ideal for beginner bonsai lovers and are fairly simple to cultivate.
Place your rosemary bonsai in a location that receives at least six to eight hours of sun each day. The indoor and outdoor rosemary bonsais require ample amounts of direct sunlight. The indoor bonsai will adapt to short amounts of sun but requires at least four to five hours of direct sunlight each day. Avoid placing the indoor bonsai near heating vents, stoves and other locations with high temperatures. The excessive temperatures can damage the tree and stunt its growth.
Water your rosemary bonsai tree regularly, preferably in the morning and at the same time each day. Generally, most rosemary bonsais require watering every two to three days. Avoid overwatering the bonsai, however. Rosemary bonsai trees prefer to dry out before each watering. Check the bonsai's soil moisture levels before watering by placing your finger one inch into the soil, near the roots. Water when the soil feels dry. Ensure that the bonsai's potting container drains well. Rosemary bonsais cannot tolerate wet feet.
Prune your rosemary tree to promote a miniature bonsai size. These rosemary trees grow fairly rapidly and can reach heights of 48 inches when left untouched. Prune your rosemary's newly growing stems, branches and trunk to promote its desired shape and size. Avoid pruning all of its new growth concurrently to avoid stunting the tree's growth.
Re-pot your bonsai annually, preferably in the early spring. Since the rosemary bonsai is a rapidly growing tree, it often will outgrow its original potting container. During the re-potting process, remove the excessive soil from the tree's roots and prune the roots back one third inch. Avoid excessive root pruning as it could damage the tree and stunt its growth. Re-pot your bonsai quickly as the roots will dry out in just a short period of time.
Fertilize your rosemary bonsai during its growing period, from early spring to mid-fall. Use a well-balanced fertilizer that includes equal combinations of nitrogen, potassium and phosphorous. Incorporate the fertilizer into the soil at half strength. Avoid placing the fertilizer directly onto the roots of the tree as this may cause root burn. Fertilize the bonsai monthly during the growing period.