Ten different horticulture therapy (HT) activities that can be adapted for preschool children, elderly adults, and intergenerational groups are outlined here. The goals for these activities included participation, self-motivation, and fun. The children's activities were designed for freedom to explore and learn and to ensure completion of the activity. The elderly adult activities were designed for flexibility to adapt to the different ability levels of the participants. The intergenerational activities were designed for group interaction. While these activities produced variable results for the children's group, the elderly adult group, or the intergenerational group, they were all successful. Guidelines are given for increasing effectiveness and success of activities when working with these populations.