Lantana is a vibrant, sun-loving tropical shrub valued by gardeners for its continuous display of colorful flower clusters from spring until the first hard frost. It is a true perennial only in the warmest climates (USDA Zones 9 through 11), where temperatures rarely dip below freezing. In Zone 6, where winter temperatures are significantly colder, Lantana is not a reliable perennial and is typically cultivated as an annual. The harsh winter climate forces it to be treated as a seasonal plant unless specific measures are taken for protection.
Understanding Lantana’s Hardiness Limits
The USDA Plant Hardiness Zone system determines a plant’s ability to survive the cold season based on the average annual minimum winter temperature. Lantana is a tropical plant with a low tolerance for freezing temperatures. Most varieties will not survive when temperatures consistently fall below 28°F, and the plant’s roots are killed by a deep or sustained freeze.
Zone 6 is defined by average annual minimum temperatures ranging between -10°F and 0°F, which is consistently lethal to the Lantana root system. Even the slightly warmer subzone 6b is far too cold for the plant to survive outdoors without protection. While certain hybrid cultivars show improved cold tolerance, Zone 6 remains outside of the plant’s natural survival range, requiring different management than true Zone 6 perennials.
Strategies for Growing Lantana in Zone 6
Since outdoor winter conditions in Zone 6 guarantee the demise of Lantana, gardeners must choose one of two main strategies for managing the plant.
Treating Lantana as an Annual
The simplest approach is to treat Lantana as a seasonal annual, allowing it to die back after the first killing frost. This method requires purchasing new plants each spring, offering a cost-effective and low-effort solution for summer color. It is practical if the plants are grown directly in the garden bed, as it eliminates the need for winter maintenance.
Overwintering Container Plants
The alternative is to save the plant by overwintering it indoors, which is necessary to preserve a specific mature plant or rare cultivar. This strategy involves growing the Lantana in a container throughout the summer so it can be easily moved before cold weather arrives. While this option requires effort and space, it provides a larger, more established plant ready for the following spring.
Techniques for Successful Overwintering
If you choose to save your Lantana, success relies on proper timing and creating the correct cool, dormant conditions indoors.
Preparing the Plant
The plant must be moved inside well before the first hard frost, ideally when night temperatures begin to drop consistently into the low 40s Fahrenheit. Before bringing the plant inside, heavily prune the stems back by one-third to one-half to reduce its size and prepare it for dormancy. Thoroughly inspect the plant for pests like aphids or spider mites, treating them with insecticidal soap to prevent an indoor infestation.
Maintaining Dormancy
The goal during winter is to induce a state of dormancy, not active growth, so a cool, dimly lit location is best. An ideal overwintering environment is an unheated basement, garage, or cool sunroom where temperatures remain consistently between 40°F and 50°F. Temperatures above 55°F may encourage weak, leggy growth, while temperatures below 32°F will kill the plant. During this dormant period, watering must be minimal. Allow the soil to dry out almost completely between waterings, providing just enough moisture every few weeks to keep the roots from desiccating. Do not fertilize the plant, as this disrupts the necessary dormant cycle.
Reawakening in Spring
When spring approaches, about four to six weeks before the last expected frost, the Lantana can be moved to a brighter, slightly warmer location. This gradual reawakening involves increasing the frequency of watering and introducing more light to prepare the plant for its eventual return outside. After all danger of frost has passed and night temperatures are reliably above 45°F, the plant can be moved back outdoors and gradually reintroduced to full sun.