Yes, a difficult question. Easy for us to answer as it's not our treasured plant! Probably best to replace it and plant another one in a more favourable spot. By the time you've dithered a new one could be thriving. Or put a new one elsewhere and give the old one just one more chance....

After frost damage in 2006, my Hibiscus had been stubborn about coming back. It finally snapped out of it with frequent feeding with a tropical plant food, plus epsom salts. Modern Miracle-Gro (not the old formula) plus epsom salts should do the same thing. Best of luck with it, Bertie.

Thanks Tugbrethil. I will try feeding it with Miracle-Gro as the soil where it's planted is pretty poor. I've just bought a new large flowered one, yellow with an orange centre, which is great, but I'd still like to revive the old one if possible.