There is hope for your hibiscus plants. They could just be dormant and leaf less and will sprout new foliage late in the spring around May once you move them outdoors and into the sunlight. The question is what type of hibiscus you purchased and what type of climate you live in. There are hardy hibiscus that will survive the winters outdoors and many new varieties are now available with huge blossoms. There are also tropical hibiscus sold as houseplants or patio plants that will die if hit with a hard frost or freeze. I suspect that you may have the hardy hibiscus as they flower late in the summer and into the fall when you purchased the plants. If you live in a mild winter climate that rarely dips below 20 degrees you can transplant your hardy hibiscus into the ground this spring and leave them outdoors all winter. The plant tag should show how to transplant from pot to ground and the name of the variety which you can look up to see if it is hardy or not. The hardy hibiscus can grow into large shrubs 12 feet tall so give them room. Either way remember that during the winter when your hibiscus looks dead it needs very little water and should be kept cool in the garage. Add more water in late spring and move the potted plants to a bright window or out on a protected deck or porch. Keep the soil moist but not wet. In late May or even June the leaves will finally sprout unless the plants really are dead. One way to check is to scratch a bit of the trunk bark with a fingernail. If you see green under the bark the plant still has life. My guess is you will enjoy late summer blooms from these plants again and will be able to leave them outdoors all winter. Keep growing, Marianne Binetti