Lantana (Lantana spp.) may remain evergreen and bloom year-round in frost-free or virtually frost-free climates such as U.S. Department of Agriculture plant hardiness zones 9 to 11. However, the plant will die back to the ground in USDA zone 7 and often in USDA zone 8 as well. If heavily mulched there, the most robust types -- such as 'Miss Huff' (USDA zones 7 through 11) -- should re-sprout from their root crowns in spring. Don't plant any lantana after late summer, though, if you want it to survive the winter in marginal zones.
Winter Care in Zones 7 through 11
In usually frost-free climates, lantana shouldn't require much winter care at all. If its leaves do get nipped by frost, leave affected foliage in place over winter to shield the rest of the plant. Whether or not the lantana has been damaged, cut it back severely in spring -- to encourage fresh new growth.
A lantana growing in colder zones usually can endure light frosts, down to about 29 degrees Fahrenheit, with little damage except possibly a hint of purple in its leaves. At lower temperatures, however, its foliage will begin to die back.
After that foliage is dead, leave it in place, surrounding and partially covering it with a noncompacting winter mulch – such as 3 to 6 inches of chopped dead leaves or 6 to 12 inches of straw. If you prefer a neater look, try cutting the dead stalks back to 1 inch high before applying winter mulch on top of the resulting stubs.
In early spring, remove the mulch and watch for new growth to begin to sprout from the ground. Once you see it, cut away the old dead foliage, if you didn't do so the previous autumn.
Winter Care in Zones Lower than 7
Once night-time temperatures begin to fall below 50 degrees F, pot up your lantana in a fast-draining and slightly acidic potting soil such as that designed for cacti. Shift it into the shade to prepare it for the dimmer light indoors. After the plant is well-established in the container and just before you move it indoors, mix 5 tablespoons of an insecticidal soap concentrate into 1 gallon of water and thoroughly spray the plant.
Where you place the lantana will depend on whether you want it to remain semi-dormant over winter or prefer to grow it as a houseplant. If you choose to keep it semi-dormant:
- Place it in a bright but chilly position, such as in a sun porch or garage window.
- Keep the plant at a temperature between 40 and 50 degrees.
- Refrain from fertilizing it and water it only about once a month or often enough to keep its roots from drying out completely.
If you choose to grow the lantana as a houseplant:
- Place it in a room where the temperature remains between 60 and 70 degrees F, lower at night.
- Position the plant on a sunny windowsill – preferably a south-facing one.
- Water it whenever its soil is dry 2 inches beneath the surface, but don't fertilize it until spring.