The plants in your hanging basket are usually all annuals which can't be saved.

It depends what you plant as well, I had some cineraria 'silver dust' just for height and also in troughs in the garden and am amazed that although looking badly in need of a haircut are still alive after -12 deg C

Nepeta cataria (catnip). Hanging baskets are the only way it will survive. Mine has become very bushy due to constant pruning, and it will survive as long as it isn't too near the ground.