REST!
Nothing more occurs. The channels of sap are closed. The tree is inactive.
Needs of the tree
Winter or structural pruning (styling): Carve deadwood if you must. But perhaps it’s best to do nothing at all and simply order a beautiful tree for Christmas from your favourite nursery — yes?
Placement
December is the first month when it seems that there is nothing to do for our bonsai. They are at vegetative rest. They accumulated their reserves in the trunk and the buds. They are waiting for the hormonal phenomenum that starts the burgeoning of spring.
Fertilizing
No fertilisers, because the roots will not absorb them. You will be able to give trace elements containing mainly Iron, Calcium and Magnesium by spraying the needles of conifers or the trunks of the leafy trees.
Watering
Take care that your trees don’t dehydrate, especially in cold greenhouse. The roots should not become desiccated. Therefore water regularly and in small quantities. Don’t drown conifers.
Activities
- Tropical trees: indoors or in hot greenhouse. Attention with the luminosity. 1200 lux per day. Regular watering and organic fertilisation.
- Conifers: you can still remove last years’ needles. Take your time and work very carefully. The small branches can benefit from wiring. It is also the moment to select the buds that will produce the spring candles. Select them in pairs by always keeping the strongest possible side buds. Remove the buds directed towards the top and base.
- Deciduous: caution when wiring. You may think you can do it, but the branches are very breakable at this time. On the other hand, you can begin structural pruning if you have lots of trees. In all cases avoid major works when it’s very cold. Protect your fragile trees — Japanese maples, for example. Mulch round their pots carefully. In Northern Europe, bury the pots or winter them in a cold greenhouse.
