In principe zijn je europese bomen bestand tegen een paar weken vorst, als ze niet in de wind staan. De termperaturen die nu buiten verwacht worden (Kouder dan een paar graden vorst) kunnen bij bonsai wel tot echte schade leiden, voornamelijk aan het wortelsysteem.
Een externe link, waar een heel verhaal over bonsai in de winter staat is de site bonsai4me van Harry Harrington:
www.bonsai4me.com/Basics/Basics_WinterCare.html
De meest relevante paragraaf:
The truth is that nearly all temperate woody species are reliably hardy down to -10°C (15F). Below this temperature all that is required is some protection for the root system which is not as frost hardy as the top growth. To become reliably hardy to these temperatures, trees must fully harden up in the Autumn by being grown outside. Trees are able to survive sub-zero temperatures by virtue of being dormant. Trees that are purchased during the winter should be kept in similar conditions to those that they had been kept in by the retailer, even if this was indoors. To put a tree outside in the middle of winter when it has previously been grown indoors and is still active would kill it.
