Heucheraholics supply almost all of their plants in one litre pots. That means you get stonking plants that are strong enough to get established quickly, they are so much bigger than the plugs and bare root plants that many other nurseries sell.
Remember to water plants in well when you plant them, this first watering is more about settling them in than keeping them moist......even if you plant them in the rain you will still need to give them a good soak.
The plant on the right is typical, some times they'll be bigger and occasionally in the Spring they'll be a tad smaller. Of course size will vary a bit according to variety, some like 'Brownies' get big quickly, others are more petite.