What to do in the garden in December
- Earth up or stake brassicas.
- Protect cauliflower curds from frost by bending over an outside leaf or using horticultural fleece.
- Continue digging over ground for spring sowing or planting.
- Force rhubarb if needed.
- Continue forcing chicory and seakale.
- Protect bay trees from frost.
- Protect from pigeons, as they are the main pest of this time of the year. The best protection is to net the whole area.
- Continue pruning fruit trees and bushes. Collect the prunings immediately and dispose or burn them. Leaving them lying around on the ground is an open invitation to disease. Bonfire ash can be used to top-dress the trees and bushes, giving them a useful feed of potash. The ash must be spread as soon as it is cool but still while it is still fresh and dry, as old wet ash will have lost most of its value.
- Spray with an organic winter tree wash, if needed. This does not have to be done every year.
- Continue pruning grape vines and use the prunings for hardwood cuttings.
- Check the supports and ties of cane fruit, grape vines and trained fruit trees.
- Continue planting or heeling in trees and bushes if necessary.
- Mow the lawn if the weather has been mild and not too wet. A very light mowing will leave the garden looking tidier and stop the grass from getting too long. New lawns, sown from seed in the autumn, can also be lightly mown too on a sunny, dry day.
- Start deep digging the soil if you are planning to put down a new lawn from seed in the spring, so that it is in workable condition and got time to settle down before sowing. The more you can walk on it, leveling and raking between now and the time of sowing, the better it is.
- Treat lawns infested with leather jackets. They feed on grass roots and basal stems just beneath the surface of the soil. The main indications that these pests are at work are brown patches of dying turf as soon as the weather turns dry.
TREES & SHRUBS
- Continue pruning roses and spray against black spot. Prevention is often the best cure and keeping the ground beneath roses free of all dead leaves or other debris is as important as spraying, as fungal spores tend to collect and over winter there.
- Plant new roses, as long as the soil is workable. Check the roses planted last month, to see that they haven’t been lifted by frost. Firm them back into the soil, if needed.
- Continue planting deciduous trees, shrubs and hedges.
- Water container plants and check for wind rock.
- Check defences against frost. Adjust screening or protective coverings if they have come adrift.
- Water pot, container and tub planted ornamental trees and shrubs in the weather has been warm and sunny. If it has been wet and windy then also check for wind rock. The latter occurs when a plant takes the full force of the wind, and a hollow forms in the soil round the base of the stems. Newly planted trees and shrubs are particularly vulnerable, as their roots have not yet had time to become established.
- Continue digging and tidying up of herbaceous beds. All leafy and soft organic material should be added to the compost heap, with any woody or diseased material placed in the bonfire or removed from the garden.
- Harvest holly with berries for making Christmas garlands and wreaths. Stand them in a bucket of water until you’re ready to use them.
- Bring forced bulbs indoors.
- Cut back late-flowering, chrysanthemums and take cuttings.
- Take cuttings from perpetual flowering carnations.
- Take root cuttings of oriental poppies and grow them on in cold frames.
- Check bulbs, corms and tubers in storage.
- Water over wintering plants in the greenhouse.
- Spread fresh gravel or grit around alpine plants.
- Lift and store dahlia tubers once their leaves are blackened by frost.