What to do in the garden in December

As the year draws to a close in December there's still plenty to do in the garden
Image: Jon Naustdalslid/Shutterstock

December is a quiet month in the garden, but there are more things to take care of than you might think. With limited daylight hours as we approach the shortest day of the year, this month's crisp wintery weather can be strikingly beautiful and bitterly cold in equal measure.

For this month's planting advice, have a look at what to sow and grow in December. In the meantime, here’s a checklist of jobs to keep you busy.

Timely Tips

Keep the garden birds fed during December
Image: Andriy Blokhin/Shutterstock

1. Dig over empty borders and prepare your soil for next year’s planting.
2. Group potted plants together in a sheltered spot in the garden to protect them from the harshest winter weather.
3. Get pruning! Wisteria, some fruit trees, roses and Japanese maples are just some of the plants that benefit from a winter prune.
4. Look after the birds - clean feeders, stock up on wild bird food and make sure they have access to fresh water.

In the flower garden

Resist the temptation to prune your hydrangeas before spring
Image: Hydrangea macrophylla 'Endless Summer — The Original' from Thompson & Morgan

• Start to winter-prune wisteria, cutting back whippy summer side-shoots to 2 or 3 buds. Favourites like Wisteria sinensis will look tidy and flower better after a good shaping. 
• Prune climbing roses now, removing diseased or damaged growth and tying in any new shoots to their support. Prune older flowered side shoots back by two thirds of their length.
• Plant deciduous, climbing honeysuckle now, but make sure to avoid any frozen or waterlogged ground.
• Prune your Japanese maple trees (Acer palmatum) if needed, as they will bleed sap if pruning is done any later.
• Leave the faded flower heads on your hydrangeas until spring, as they provide frost protection to the swelling buds further down the stems.
• If any of your rose bushes suffered from blackspot or rust during the summer, gather up and remove any fallen leaves still on the ground to reduce the chance of spreading the infection next year.
• Keep checking over stored dahlia tubers, keeping an eye out for rot.
• Move containers of shrubs or bedding planters to sheltered spots; clustering them together helps protect the root systems from frost damage.
• Check climbers and climbing shrubs are securely attached to their supports with ties.
• Harvest holly with berries for making Christmas garlands and wreaths. Stand the berry covered twigs in a bucket of water until you're ready to use them.
• Take root cuttings of oriental poppies and grow them on in cold frames.
• Take hardwood cuttings from suitable trees and shrubs.
• Spread fresh gravel or grit around alpine & rockery plants.

In the vegetable garden

Lift and heel in your last leeks during December
Image: Leek 'Musselburgh' from Thompson & Morgan

• Lift your last leeks and parsnips before the soil becomes frozen, and heel them into a trench beside a convenient path. They’ll keep for several months like this and can be easily brought indoors when required.
• Remove yellowing leaves from your winter brassicas — they’re no use to the plant and may harbour pests and diseases.
• If you haven't already, cut down dead asparagus foliage and the top growth of Jerusalem artichokes. Order your asparagus crowns now for planting in spring.
• Dig over empty borders and pile well rotted manure on top - let the worms and frosts break up the clods of soil.
• Dig a trench for next year’s beans, fill it with compostable kitchen waste (not cooked food) and re-cover with soil. This will rot down and dramatically improve the growing conditions.
• Cover winter brassicas with netting to protect them from pigeons.
• Keep fleece to hand to protect hardy salad crops such as Lettuce 'Winter Gem', winter land cress, purslane, and corn salad (lambs lettuce) on cold nights.
• Protect any remaining celery plants left in the soil by covering with straw or fleece.
• Cover heavy clay soil with polythene to keep it drier and allow winter digging.
• While many parts of the garden and allotment are cleared, use this opportunity to install a permanent network of hard-wearing paths.

In the fruit garden

Prune grape vines during December to encourage heavy cropping in the summer
Image: Grape 'Dornfelder' from Thompson & Morgan

• Now is the perfect time to prune fruit trees to maintain an open, balanced structure and encourage quality fruit production. The exception is plums, cherries and other stone fruits that should not be pruned until the summer to prevent silver leaf fungus. Use clean, sharp secateurs to avoid damaging your trees.
• Prune grape vines.
• Construct a screen of clear polythene over wall trained peaches and nectarines to protect them from wet winter weather, which spreads the peach leaf curl fungus.
• Lift and divide established clumps of rhubarb to renew the plant's vigour. Sections taken from the outside of the plant are better than those from the centre.
• Protect the tips of fig tree branches. They will carry the fruits for next year and are susceptible to frost. Cover with fleece or straw.
• Apply glue bands or grease bands to the trunks of fruit trees to prevent wingless female winter moths climbing the trunks and laying their eggs in the branches.
• If your strawberry plants are over 3 years old, order some new varieties to replace them. Old strawberries can harbour diseases and tend to lose vigour and productivity.

In the greenhouse

Keep your greenhouse snow free during December
Image: Starover Sibiriak/Shutterstock

• If you haven't already done so, clean out the greenhouse thoroughly. Wash the glass, the floor and the staging with horticultural disinfectant to kill any overwintering pests and diseases.
• Wash and disinfect capillary matting before storing it away.
• Brush heavy snow off the tops of greenhouses and cold frames to prevent the glass getting damaged.
• Insulate outdoor taps or turn them off at the mains. Pack away hoses that are not required.
• Ventilate the greenhouse on warmer days to reduce humidity and the risk of disease.
• Work in some manure to greenhouse borders to prepare them for next spring. Leave enough space to add compost later on.
• Propagate perennials from root cuttings including phlox, oriental poppies and mint.
• Water plants sparingly to maintain as dry an atmosphere as possible.
• Keep an eye out for aphids overwintering on your plants, remove them by hand or use a pesticide.
• Protect your poinsettias from cold draughts and allow them to dry out slightly between waterings to make them last well into January.

Looking after your lawn

Don't walk on your lawn if it's frozen during December
Image: Deryabin/Shutterstock

• Avoid walking on your lawn when it’s blanketed by heavy frost or snow, as this damages the grass.
• If it's a mild winter, continue to cut the lawn as it grows, but raise the height of the mower blades.
• Spike lawns with a garden fork to improve drainage and aeration.
• Keep clearing leaves off the lawn to let the light in and prevent dead patches appearing.
• Send your lawnmower and shears to be serviced and sharpened while they’re less in demand.

Other jobs about the garden

Keep your bird feeders topped up for feathered friends during December
Image: Nature's Market Wild Bird Nut Feeder from Thompson & Morgan

• Wash down all of your garden tools and give them a wipe of linseed oil on the wooden and metal areas to help prevent rusting.
• Choose a dry day to clear out the garden shed in preparation for the spring.
• Plant bare root edible hedging now while the plant is dormant.
• Check the security of your shed. This is particularly important in winter when you visit it less often.
• Repair fences and apply a wood preservative to prevent them from rotting.
• There’s still time to clean out water butts before they fill with fresh rain water over winter.
• Get rid of slimy patches on the patio and paving by scrubbing with a broom or blasting with a pressure washer. For an easy alternative try a liquid patio cleaner.
• Check tree ties and stakes to ensure that trees are still secure following strong autumn winds. Tighten or loosen ties as necessary.
• Wash and disinfect bird feeders and bird tables. Clean out bird baths too.
• Hang fat balls and keep bird feeders topped up with wild bird food to attract birds, who will in turn eat pests in your garden.
• Build or buy a compost bin. Continue to collect fallen leaves and add to leaf bins or the compost heap to rot down.
• After pruning fruit trees use the twigs for pea sticks or shred them for your compost bin.
• Turn your compost heaps to mix the ingredients and help the contents to decompose.
• Cover compost bins with a piece of old carpet or some plastic sheeting to prevent the compost becoming too cold and wet to rot down.
• Make a pile of old logs in an undisturbed corner of the garden to provide shelter for toads and other wildlife.
• Collect brightly-coloured stems and berries for your Christmas decorations.
• Did you know the colourful wrappers of Quality Street sweets are compostable? They’re made from cellulose, derived from wood pulp, so rather than chuck them in the bin, add them to your compost heap!

From your armchair

Order apple trees to start your own mini orchard
Image: Apple 'Golden Delicious' from Thompson & Morgan

• Carefully plan your vegetable garden’s crop rotation for next year to avoid a build up of pests and diseases.
• Order your flower seeds and vegetable seeds for next year - reflect on what worked well and what didn't, and don’t be afraid to try new ideas.
• Take an inventory of tools and equipment that you need for next year. Add them to your Christmas list!
• Order apple trees now for planting in early spring. If space is limited, try growing dwarf fruit trees.