What to do
Spikes of early flowering Iris reticulata and crocus are already spearing through the ground, with scillas and grape hyacinths. If the earth looks sour, tickle the ground up around the bulbs and remove any seedling weeds.
Continue to mulch thickly round herbaceous perennials, such as hosta and rodgersia, both of which are quite greedy plants. The mulch feeds, but it also suppresses annual weeds and improves the texture of soil.
Keep greenhouses well ventilated – a constant temperature is what you're aiming for. Winter sun can build up a surprising amount of warmth. If you close the vents in time at the end of the day, you can trap some of this warmth to use through the night.
Gently force batches of early spring bulbs by bringing pots of them into a cool greenhouse. Dwarf narcissi, hyacinths, crocus and iris all respond to this kind of treatment. When the flower buds begin to colour up, you can bring the bowls into the house.
What to see
The winter lecture series opens this month at the Oxford Botanic Garden with the magnificent Fergus Garrett, head gardener at Great Dixter, talking about the past, present and future of this extraordinary place. Tickets cost £10 and the talk starts at 8pm on 27 January. To book, call 01865 286690 or visit botanic-garden.ox.ac.uk