A Eugenia plant (Eugenia myrtifolium) is a good choice for a topiary because its small leaves and delicate branches respond well to training and shearing. This plant grows outdoors year-round in U.S. Department of Agriculture plant hardiness zones 10 and 11 but can also grow indoors in a container. A Eugenia plant is an Australian evergreen with small, glossy green leaves. Although it can grow into any shape, the plant responds especially well to training as a ball, either a single ball or several balls connected by a central, bare stem. Eugenia is quite resilient and requires little special care when given the right growing conditions. It can grow well in full sun outdoors, but in regions with hot summer sun, a spot that gets full sun for the morning hours, followed by partial shade in the afternoon, is ideal. An outdoor-grown Eugenia topiary thrives in any type of garden soil that's well-drained and does poorly in soil that tends to stay wet for long periods. If your soil is high in clay, adding sand at planting improves its drainage.