what size hydrangea petiolaris to buy?

replying to L3iH, Iggy wrote: Doesn't matter, except the smaller is easier to plant and therefore more prone to you properly digging too large a hole for the best establishment. However, I find the larger plants to be more pot-bound, almost no soil, and needing more scoring or tearing.

Just to update - prompted by a comment that sometimes vendors simply put a smaller plant in a larger pot with lots of compost, I called the company (begins with T-M) and asked how old the two different size pots were. The person I spoke to was very helpful about ideal planting needs and agreed the smaller_size would be better as it would be less "set in its ways" so to speak and so would settle in to a new location more quickly (particularly given the limitations of my tiny garden). Hopefully in a year or two I'll have a happy hydrangea, however big it is!