Q.hibiscus
What is an hibiscus root called and how do I plant it? What part is up and how deep do I go?
Certified GKH Gardening Expert
If you are just receiving the plant (i.e. through mail order), it most likely will come as a bare root plant. This article has more information about these types of plants: https://www.gardeningknowhow.com/ornamental/trees/tgen/bareroot-planting.htm
It sounds like you're confusing the hibiscus root with a corm or rhizome. Corms or rhizomes are usually rooty-looking things which have the ability to sprout a new plant when they are buried in the ground. Hibiscus roots are just roots, and normally you can't start a new plant from one. The methods for starting hibiscus are either from cuttings or from seed. https://www.gardeningknowhow.com/ornamental/flowers/hibiscus/hibiscus-propagation.htm
But hey, you can try if you want. Just lay the root under the soil maybe 6 inches, and keep the soil moist and warm -- who knows, it may sprout.