The bottlebrush tree, or Callistemon, is a low-maintenance tropical tree that requires little hands-on care after its initial planting period. During the first few weeks after planting, however, it requires a bit of tending by regular watering and through initial fertilization of its roots. While the need to water the tree regularly stops after a few weeks, the need for fertilizing continues several times a year. This consistent application of fertilizer is necessary to provide the drought-resistant tree with the nutrients it needs to bloom the bright red flowers it is known for.
Water the bottlebrush tree daily during the first week after planting. Give the plant enough water to saturate the roots, but take care not to pool the water around the base of the tree in the process.
Reduce the rate of watering to two or three times weekly for two to four weeks after the first week. As with the first week, thoroughly saturate the roots of the tree with the water without pooling.
Stop watering regularly after the initial planting process. After the initial planting, the tree needs little water and can gain all that's required through natural rainfall. Overwatering will make the tree prone to fungus.
Fertilize the tree upon initial planting and then two to four times a year by sprinkling 1 to 3 pounds of a low-phosphorous fertilizer over the root system. For best results, fertilize the trees at the beginning of the spring, summer and fall.