When it comes to gardening THEY (internet experts as well as seed package authors) take all of the quirks and qualities of a variety and bundle them together and spit out an average for us (the customer).
I am in South Texas and have beds full of annuals that (I leave to go to seed) return each spring.
Every year I see masses of hydrangeas being purchased and wheeled out the doors of various garden centers.
I speak with whoever takes care of the plants, explain what I need and receive advice.
I have tried for over 5 years now to start just ONE by purchasing different varieties from different vendors and trying the different "micro climates" of my yard.
The master gardener working out of our local extension office has even come out, looked around and sampled soil.
No reason for all the failures.
I give up.