The trees are now going into dormancy, the period of least growth.

Keep your trees well protected from freezing temperatures.   Keep checking the soil - your trees might require watering in the absence of rain.   Enjoy Christmas but do not forget your trees in all the excitement.    Look at your trees while not in leaf - you can then better see the structure and determine the future shape.

Shohin and mamé, (smaller size trees), should be under cover - this allows for better control of moisture levels.    January is probably one of the worst months of the year for your bonsai.    During the winter most trees need to be well protected from long periods of freezing temperatures.    Place in a cold greenhouse or polytunnel or cover them with insulating material such as horticultural fleece. If there is little or no rain, occasional watering should keep them moist but not wet.

Keep checking for insects, particularly on deciduous trees (like the oak).    To overcome these unwanted elements, give each bonsai a tar wash using a substance such as diluted Armillatox or Jeyes Fluid.    You will have done this before the winter started and can now do it again. This helps eliminate the risk of infestation of pests and onset of disease.

Outdoor trees will consume little water but watering might be required in the absence of rain.    If watering is necessary, ensure that it is done early in the day; this allows time for drainage should temperatures drop below freezing at night.