I received a hibiscus (tree shape, about 3' high) - not sure what variety, in the autumn last year. It had been outside planted in the earth for the summer and didn't have very much of a root system.

I potted it up, and put it in a south facing area where it'd get the most sun and... nothing! No new growth, no flowers, one or two dropped leaves, but nothing else for over 9 months.

I know it's alive because the leaves do wilt if it doesn't get water, and recover when they do.

I intend to move it outside once the weather warms up a bit.

Any ideas on what I can do to get some life out of this plant?

Thanks in advance!