Lantana is a popular, colorful shrub prized for its extended bloom season and ability to attract pollinators. Native to tropical and subtropical regions, its bright clusters of flowers thrive in hot, sunny conditions. Lantana’s winter survival depends entirely on the local climate. Gardeners in colder regions often treat it as an annual, replanting it each spring. In milder climates, specific preparation is necessary to ensure the plant successfully navigates the dormant season.
Understanding Lantana’s Cold Tolerance
Lantana’s winter survival is determined by the temperature threshold of its root system. It is classified as a perennial in USDA Hardiness Zones 8 through 11, where winter temperatures remain relatively mild. In these zones, the above-ground foliage typically dies back after the first hard frost, but the roots remain viable underground, allowing the plant to return in the spring.
The plant enters dormancy when temperatures consistently hover around the freezing point. The root system, however, can suffer severe damage or complete failure if the ground freezes solid for an extended period. Gardeners in zones colder than 8 should assume the plant will not survive an outdoor winter, as temperatures dipping into the low 20s Fahrenheit can be lethal to the crown and roots. Understanding this hardiness limit dictates whether a gardener prepares the plant for outdoor survival or opts for indoor storage.
Preparing Established Plants for Outdoor Survival
In zones where perennial survival is possible, the goal is to insulate the root crown from damaging cold snaps. This preparation must be completed before the first hard frost arrives, as the roots need protection before the ground temperature drops significantly. Pruning should be executed conservatively; only remove about one-third of the growth to eliminate spent flowers and damaged foliage, rather than cutting the plant to the ground.
The application of a deep, protective layer of mulch is the primary step for in-ground plants. Use organic materials like shredded leaves or straw, applying a layer approximately four to six inches deep around the base of the plant. This mulch stabilizes the soil temperature and prevents the destructive cycles of freezing and thawing that can heave roots out of the ground. As the plant enters dormancy, reduce watering dramatically to prevent the roots from sitting in saturated soil, which can lead to rot.
Methods for Overwintering Lantana Indoors
Gardeners in colder regions must bring their lantana indoors to preserve it, treating it as a tender perennial. Before the first frost, container-grown plants should be moved inside, or in-ground plants can be carefully dug up and potted. The first step involves a severe cutback, pruning the stems down by one-half to two-thirds of their size to reduce the plant’s mass.
After pruning, inspect the plant thoroughly for pests such as aphids, mealy bugs, or spider mites, which can rapidly infest indoor environments. Treat any detected pests with insecticidal soap before the plant is relocated inside. Two main methods exist for indoor storage:
Forcing Dormancy
Place the plant in a cool, dark location like a basement or garage where temperatures remain between 40 and 50 degrees Fahrenheit. Water the plant sparingly, perhaps once every four to six weeks, only to keep the soil from drying out completely.
Active Growth
Place the plant in a brightly lit window to encourage continued, though slower, active growth, requiring slightly more frequent, yet still reduced, watering.
Spring Care and Re-establishing Growth
Once the threat of hard frost has passed and nighttime temperatures are consistently above 45 degrees Fahrenheit, the lantana can begin its transition back outdoors.
Container plants that were overwintered indoors require a gradual reintroduction to the elements, a process known as hardening off. This involves placing the plant outside in a sheltered, shady spot for a few hours each day, slowly increasing the exposure to sunlight and wind over a period of seven to ten days.
For plants that remained in the ground, the protective layer of mulch should be pulled back in early spring to allow the soil to warm up. Assess the in-ground lantana by scratching the bark of the stems to find green, living tissue, and prune away any growth that is clearly dead and brittle. Lantana is slow to show new growth after winter dormancy; new shoots often do not emerge until late spring. Once new growth is visible, resume a regular watering and fertilization schedule.