If the stems are green, the plant is capable of sprouting buds. Cold-damaged hibiscus, crotons, ixoras, tibouchinas and other more tropical plants can take months to regrow when killed back to the ground. They have to develop new shoots from dormant buds. Keep the soil moist and provide a light spring feeding. I am seeding a lawn and was told to put down limestone to prepare the soil.
Limestone is used to adjust the soil acidity.
In Florida we normally do not add lime of any sort without having the soil tested. Some plants have specific acidity needs, and adding lime without benefit of the test may affect growth. You can test the acidity yourself with kits available at garden centers, or soil can be tested at garden centers and through you local extension service office for a small fee. After testing, you can add lime if needed and till it into the soil before sowing the grass seed. My recently transplanted arugula is developing stalks of flowers.