Plants in the cullumia genus typically prefer well-drained soil, moderate to full sunlight, and regular watering that allows the soil to dry out somewhat between watering sessions. Begin by loosening the soil and enriching it with organic matter. Space the plants according to their mature size to ensure adequate airflow. Plant at the same depth they were in their containers. Water thoroughly after planting and mulch to retain moisture. Being adaptable, most cullumia species thrive with basic care, but always check the specific needs for the species you choose.