Starting from left to right:

Brown pot: pastel mix impatiens
Burgundy pot in back: Endless summer hydrangea, white bacopa, rosebud impatiens, white nancy dead nettle
Terra cotta pot (right side of image): Dianthus caryophyllus (clove pink), Million Bells (Calibrachoa) tiki soft pink, echinacea pink double delight and purple campanula (bellflower)

Will hydrangea survive in a pot year to year or will it have to be put into the ground over winter? How big will it get in a pot?

Yes, hydrangea will survive year after year in a pot...so long as the pot is large enough. The size of the plant is dependent on the variety of hydrangea you select. There are dwarf varieties (e.g., Cityline Rio Hydrangea) that only get 3', while others can grow to 10' tall and wide. The size of pot required is dependent on the variety of hydrangea you select. The larger the plant, the larger the pot required.

Thank you very much. Next spring my flower pots will have the dwarf variety.