Locally...zones 5-6-7- most plants will reveal within
45 days of a consistent temp of 50 degrees.
And they will thrive in the temps above 50 degrees and slow a bit when the temp hits in the 90s.......but wait there is more.....while the plant is not putting out foliage; it is going crazy putting out roots.
However the SITING OF THE PLANT Makes 100 percent of the difference with the size as well as the growth rate of this plant.
Example:
A parent plant in my area which pups which has been shared with experienced
horticulturalist locally, have all shown different growth rate and vigor in their gardens........all determined by siting the plant in a desirable area.
Some sites are good and some are not so good
My plants are small in comparison.
Spring Basjoo growth by
Hostafarian, on Flickr