I have a huge gardenia bush with typical white flowers, but right now it has one large growth that is a bulbous red growth with tentacles at the top. It looks kind of like a seed pod.
Yes, this is a seed pod! Most people will trim these off, since the seeds will not likely resemble the parent. This is usually done as the flower dies, since this diverts energy from leaf production to flower production.
Some choose to use these as a natural die, however.
https://www.gardeningknowhow.com/ornamental/flowers/gardenia/removing-spent-blooms-on-gardenia.htm
https://www.gardeningknowhow.com/ornamental/flowers/gardenia
Last fall I transplanted a small gardenia to a spot better suited for it. It survived and now (March) has some small leaves,but it looks a little scrawny. Should I leave it alone or could I shape it a little? Thanks
This can be done a little later in the year. Pruning will usually take place in summer.
https://www.gardeningknowhow.com/ornamental/flowers/gardenia/when-to-prune-a-gardenia.htm
I need to know if my gardenias can be saved. They have some kind of fungus. Is there anything I can put on them to stop the fungus?
It likely is a mealybug infestation. Try spraying the plants with Neem oil.. These articles should help:
https://www.gardeningknowhow.com/ornamental/flowers/gardenia/gardenia-pests.htm
https://www.gardeningknowhow.com/plant-problems/pests/insects/outdoor-mealybug-control.htm