What to do in the garden in DECemBER
It’s definitely getting colder, the short days of December have arrived, and most gardens are well past their best by now. But while it’s time to rest up for some, there are still plenty of gardening jobs to get on with this month, including looking after your existing plants, planting or ordering new ones for next year, and carrying out some regular maintenance.
Trees and shrubs
If the weather is mild and your garden soil is in good shape, you can still plant root-wrapped trees, bare-rooted hedging plants and shrubs this month. Trees that have been staked should be checked to see if they need replacing or the ties need tightening or slackening off. If you live in the country, check for damage caused by animals, such as rabbits, rodents, and even deer, who will eat bark off young shrubs or trees when other food becomes scarce. You can protect the trunks with purpose-made tree guards. Meanwhile, ornamental trees and shrubs in tubs still need to be watered in December and if it has been windy, check for wind rock, which is when the rocking motion of the tree in the wind produces a hollow in the soil. Young trees are especially vulnerable, so build up the soil again if necessary. December is also a month to take hardwood cuttings from trees and root cuttings from shrubs, and you can also start pruning fruit trees (apart from ones bearing stone fruits) and climbing shrubs like clematis. Winter shrubs, such as sarcococca confusa (Christmas box or sweet box) can also be planted now.
Perennials, biennials and annuals
Perennials that are cold-hardy don’t need any special care this month or over winter, but spreading a layer of mulch when the soil freezes will help prevent winter damage, especially during a protracted cold season. You can leave the dead stems of your perennials standing through the winter as plants such as black-eyed Susan (Rudbeckia) and purple coneflower provide food for birds. Clear the ground of seeds around biennials such as Foxgloves (Digitalis purpurea) or Mullein (Verbascum) this month and collect any seedlings that have come up if you want to move them to another part of the garden. If you leave this job til spring, they won’t recover. December is also a good time to trim annual plants and remove foliage to prevent them from harbouring diseases over the winter. Spread mulch to feed plants for the coming seasons, making sure you also cover bulb beds as frost can fracture the soil and expose the bulbs.
Vegetables and fruit
In December, you can lift the last of your parsnips and leeks, remove any yellowing leaves from brassicas, and cover winter brassicas with some form of netting to protect them from hungry pigeons. Any celery plants still in the ground can also be protected with straw or fleece and if you haven’t already done so, cut away any dead foliage on asparagus plants. Clumps of established rhubarb can be lifted and divided into smaller clumps now. If you’re planning to grow beans, this is the perfect month to decide where you will grow them; dig a trench, fill it with kitchen compost, and cover with soil to rot down in time for spring. Blueberry shrubs can be planted now and will do especially well in acid soil. Delicious and nutritious, blueberries also add a bit of colour and bring pretty white flowers. Raspberry canes are dormant at this time of year, so it’s a good time to get them in the ground ready for next year. December is also a good month to prune apple and pear trees, but not fruit trees that bring stone fruit in the summer.
Grass is incredibly hardy and resilient but it’s best to avoid walking on your lawn if it is covered with snow or is frozen, as this can cause permanent damage. In milder weather, the grass may continue to grow and you can even lightly trim grass in December, just make sure to raise the mower blades to a higher setting. Spike the lawn to help aerate the ground and improve drainage and continue to rake away dead leaves and any other material that can prevent light getting to the grass. This is also a good month to eradicate pests such as crane fly as the grubs feed on the roots of the grass killing growth and leaving your lawn covered in brown patches. Make sure you use an approved pesticide and follow the manufacturer’s instructions.
Other bits and bobs
Clean your hard-working tools and apply some linseed oil to wooden and metal parts; this is good for the wood and will prevent metal parts from rusting. Take the opportunity to clean wooden fences and apply a fresh coat of preservative if the weather’s dry; empty and clean water butts, and wash and disinfect your bird feeders ready for winter. December is also the ideal month for some general maintenance and cleaning of hard landscaping. Get rid of built up dirt, moss and leaves from the patio and give the area a thorough clean with a pressure hose. Paving can also be washed down now. Inspect hard landscaped areas to see if bricks, timber, gravel, metal or stones need to be replaced and if you’re considering redesigning your garden, this is an excellent time of year to call in professional landscapers instead of waiting until spring when everyone’s busy.
Of course, December is also a time for you to put your feet up and plan ahead for next year. One of the joys of gardening is deciding what to grow and this is the ideal month to order new plants or seeds in plenty of time for the planting season, especially if you want to bring things on in the greenhouse. If you’re thinking of planting apple trees, you can order your tree now for planting in spring. And remember, with Christmas just round the corner, you can always add plants, new tools or other equipment to your wish list!