Just wondering how fast Hydrangea grow?

My son bought my wife a potted one foe mothers' day. It has 4 stalks and 4
large pom-poms in bloom. I have a rather large one already outside that's
4-5 ft. tall, 6 ft. across with dozens and dozens of stalks.

How soon, (years?) will it take to get as big as the large one outside?

Just want to plant it in a proper location.

Thanks...