Garden Diary: December
Bulbs and Flowers
Protect any choice, border-line hardy bulbs and perennials with a dry mulch, securing with netting if necessary.
Keep alpines free of fallen leaves. They hate to be wet in winter and could rot.
Sow sweet peas now for early, bigger plants. When the first leaves appear, move them to an open frame and only cover when really wet or very cold.
Collect seeds of hardy cyclamen hederifolium from those curly stems. Sow fresh seed in half pots of very gritty compost and place in a sheltered spot. They may take three years to reach flowering size, but yearly sowings will give a succession of new plants.
In the house: Reduce watering and make sure that your more tender house-plants are not left between the curtains and the cold windows at night. Take special care of your lovely Christmas poinsettias. A chill or a cold draught can be very damaging. Keep them away from hot radiators too.
Greenhouse and containers
It’s time to insulate with bubble wrap. If you don’t heat, be prepared to add extra layers of fleece to more tender subjects if freezing conditions set in.
Regularly remove fallen leaves or stems and continue to check weekly for mould. Let some air in on warmer days.
Plant roots in pots can freeze: this can be fatal for evergreens which will want to take up water in milder spells. If the weather turns very cold, bubble-wrap the pots. Make sure they are raised onto feet or bricks, cluster together and bring them as close to walls or fences as you can to give a little more warmth and shelter.
Tree, shrubs and climbers
Protect border-line hardy shrubs with straw, hessian or fleece. Plastics should only be used for very short spells if needed. The insulation material can be supported with a bamboo frame or wigwam. In mild spells, unwrap and let the plants get some light and air.
It’s a good month to plant new hedges and to replace any dead or weak plants in existing hedges while the ground is still warm and the soil moist. Root-wrapped specimens are available this month. They are more economical and establish well. Remember to keep new plantings well watered, even through the winter if it’s dry.
New roses are now in store, later this year, due to our warm autumn. Plant them any time that the soil is not frozen hard. You can also make any necessary moves of trees and shrubs before the soil freezes.
Start pruning late-flowering deciduous shrubs. Pruning of acers and birches should be carried out soon – before the sap starts to rise. They will bleed if cut too late.
Cut back leggy growth on roses to avoid wind-rock.
If you like to grown your own, try some different soft fruit bushes this month. You will find a large selection at the garden centre. It’s worth checking from time to time over the winter and firming them in again if frosts cause them to lift.
Prune grape vines as soon as the leaves are off.
Other jobs around the garden
As well as supplying bird food, make sure that fresh water is available. The water in birdbaths may need to be thawed as temperatures reach freezing point. Blackbirds and winter migrants like redwings and fieldfares will appreciate any pieces of fruit that you can spare.
If you have compost or leaf-mould that’s ready, spread it over the soil now. It will improve the texture, helping light soil to retain moisture and heavy soil to breathe.
Don’t forget how attractive twigs, foliage and berries can be in the house. Twined stems of the much maligned common ivy look good for a long time..especially when embellished with the odd bow or decoration.