To winterize a ground-grown perennial hibiscus plant, cut the stem, mulch the area, and remove the mulch during spring. Begin winterizing while overnight temperatures are still more than 45 degrees Fahrenheit. Tropical hibiscus plants require a move indoors to protect them from the cool winter temperatures.
- Cut the stem
Cut the stem of the hibiscus plant all the way to the ground using a pair of gardening shears. Alternatively, leave 12 inches of the old stem above ground level. The best time to cut the plant is just before the first frost and when overnight temperatures are still more than 45 degrees Fahrenheit.
- Mulch the area
Apply a 12-inch layer of mulch to the plant area. Use shredded leaves, straw or shredded bark for effective mulching. The mulch controls the temperatures, ensuring that the plant is not too warm and does not freeze due to the cool temperatures.
- Remove the mulch
Wait for spring before removing the mulch. Fertilize the plant with an organic fertilizer to promote new growth. Alternatively, use a 10-20-10 formula to fertilize. Water the plant regularly, and spray it with pesticides during new growth. Ensure that the overnight outdoor temperatures are greater than 45 degrees Fahrenheit before removing the mulch.