Prune lantana lightly during the summer and extensively in the spring, according to the Clemson Cooperative Extension. To prune extensively, cut lantana back 6 to 12 inches from the ground.
Lantana needs light pruning throughout the summer to encourage repeat blooming. Prune up to a third of the plant during the summer months. After pruning, water and lightly fertilize the lantana to encourage blooming. Never prune extensively in the fall, as this reduces the cold-hardiness of the plant and makes it susceptible to damage, disease and death. Lantana should be grown in full sun. The plant may develop powdery mildew when grown in the shade.