Našiel som na túto tému veľmi dobrý článok (v angličtine), tu je link:
https://www.evergreengardenworks.com/frzekill.htmA záver je:
From these 5 points I believe it can probably be seen that the optimum winter handling of Bonsai from temperate plants are:
Allowing the plant to properly enter dormancy and "cold harden". Exposure to the first frosts of the fall are particularly important.
Storing the plant (remember optimally) well watered in an enclosed, temperature controlled area where the temperature is held at 1 to 10C (34 to 50F) throughout the winter to allow the appropriate temperature and time for dormancy to be broken, to keep the temperature from falling too low and damaging the roots, and to keep the soil from freezing to protect the shoots from dessication injury.
Removing the plants from this protected area when the temperature conditions for growth return.
Takže prvé prízemné mrazy by stromčekom ublížiť podľa toho nemali.