Hibiscus plants should be transplanted whenever they are not getting enough sun, or when they are overcrowded--or even when they're just not doing well where they are. You first need to determine the best place to move it, and then you can decide the best way to transplant it so that it will not be harmed by the move.
Transplant a hibiscus in the proper time of year and weather for your climate. The proper time to transplant the hibiscus is anywhere from late August to late October, depending on how cold your climate is This varies with each country and climate, as hibiscus is grown all over the world in climates that aren't too cold for a tropical plant. Hibiscus plants like warm and sunny climates, but there are hardier versions for somewhat colder weather zones. Check with a local nursery for your best time to transplant.
Choose a good location. Hibiscus need good drainage--they don't do well in standing water nor do they like too much shade. Never plant them where they will be hit by salt spray. They grow out as well as up, so they need lots of room for their roots as well as their branches. They should be planted in a location where they will not be subject to constant wind.
Cut the branches back to about 1/3 of their size. This helps to keep the nourishment closer to the roots and the strongest parts of the plant. Dig a trench around the plant that goes out about 1 foot per inch of trunk diameter. This trench should be far enough out, after pruning the plant, that the whole bush is encircled.
Dig straight down with a very sharp spade--not at a slant. This will help you to avoid harming the roots. Go slowly and be careful of the roots as the reason that most plants die after transplantation is damaged roots. Be very careful of the roots as you lift the plant up. Be sure to retain as much dirt around the roots as you can.
Wrap the roots with gardening burlap and twine or other natural fiber fabric and twine. This keeps the roots together and the dirt in place. Carefully ease the plant up and onto a piece of fabric and lift the corners and tie it gently.
Dig your hole so that the plant sits at the same level on the ground as where it was originally located. It shouldn't be higher or lower in the ground than it was before. Make sure the bottom of the hole has nice loose soil so there will be good drainage, which is imperative to hibiscus plants.
Place the plant in the hole and fill it 3/4 of the way up with dirt. Add water and then tamp the dirt down so that any air pockets are pressed out. You should use stakes to hold the plant upright when transplanting unless the plant is very small. Fill the rest of the hole up with good soil mixed with peat moss.
Water your newly transplanted hibiscus every 2 days for the first 6 weeks. Water until the ground doesn't quickly soak up the water or until it's well saturated. Let the ground dry thoroughly before watering again. It should feel dry and crumbly in your fingers when it needs watering. Your plant should do well in its new home now.