Answer: Wisteria plants can be a bit slow to take off. They are setting down a good root system to support their growing top. They need to be planted out in their outdoor location if they are not already. You will most likely find that this year and especially next, the tops really take off and grow.
Blooming age will vary considerably due to soil, seedling genetics, light intensity, etc. Don't buy film to take bloom pictures any time soon, it will probably be a few more years.
Thanks for the question and good luck with those wisterias.
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