What to do in December in the garden

December feels like a pause in the garden, but you have serious work to do against frost and freezing. This month is about preparation, not repair: protect your garden against freezing, feed birds and clean your tools. Many gardeners make mistakes in December that they regret in January, especially if they still prune in frost or bring tender plants inside too late.

December also brings rest: your growing season is over, so no pruning, no sowing, no feeding. Time to think about what worked well and what must change next spring. Maybe you want to sketch your spring planting now.

Frost protection: which plants need shelter?

December brings the first hard nights and temperatures below freezing. Not all plants tolerate this. Mediterranean plants (olive or Olea europaea, oleander or Nerium oleander, myrtle or Myrtus communis) and tender container plants need shelter. Do not use plastic, it traps moisture and causes mould. Use hessian, evergreen conifer branches or tulle.

Mediterranean container plants do not survive plastic covers, they get too steamy. Better: place them against a wall on the south side, where day-night cycles help, and cover with hessian or fleece. Tulle lets light and moisture through. Place tender containers against the house, not in the middle of the terrace, it freezes harder there. Garden-grown plants (hardy olive, Spartium junceum) survive without cover in Flanders and the Netherlands, but their flower heads and top shoots freeze. That is ok, they regrow. With cover you prevent that bother.

Bird feeding: now it really matters

Once December arrives, bird experts call this season hunting season for raptors and food shortage for songbirds. Nuthatches, blue tits and great tits need many calories to survive the night. They sleep with fluffed feathers forming an air buffer. With food you meet their energy needs.

Feed your garden all winter (December through March). Peanuts or nuts, seeds and suet provide energy. Do not use mouldy seed. Place feeders under shelter (branches, a small roof) so birds can feed safely and the food stays dry. Empty and clean feeders at least every two days, leftover food attracts rats and disease. Blue tits sometimes attack each other at the feeder; place several feeders apart so subordinate birds get a turn too.

Clean and maintain tools

January is traditionally the month for pruning, so you must prepare in December: secateurs, saws and spades clean and sharp. Dirty tools spread disease from plant to plant. Saw teeth rust if you leave them wet.

Clean everything with hot water and a brush. Sharpen secateurs, saws and spade edges with a file, or have them professionally sharpened. Take a file outside and sharpen secateurs on the spot, do not wait until January. Treat wooden handles with linseed oil so they do not rot. Bring your tools inside once you no longer need them outdoors, left outside they work poorly in ice and frost.

Christmas tree with rootball: can it stay outside?

Many gardeners want to plant their Christmas tree in the garden after the holidays. This works, but not if you keep it in the living room in December and then dump it straight in the ground. Christmas trees undergo two shocks at once: from warm to cold, and from pot to ground. They cannot recover from both simultaneously.

A Christmas tree in a pot with a rootball is usually a common spruce (Picea abies). Indoors it should stand for two weeks at most. After the holidays place it in a cool garage or shed (5-10 degrees) and keep the rootball moist, indoors it dries out quickly because of central heating. Plant it around mid-February in the garden in a prepared wide pit (about twice as wide as the rootball, not deeper). Mulch with compost. Water until May. Small Christmas trees (under 1.5 metres) often work well; large ones (2 metres and more) recover less easily from the move, so keep the rootball extra moist and give them an extra week in the cool space before planting.

Pruning in December: why you wait until February

December tempts you to prune, especially if the weather is mild and you see branches you have long wanted to cut. Forget it. Frost and freezing are coming, and pruning wounds do not heal before March. A pruning wound is an open door for disease: Cytospora (canker), Nectria (red knob), bacterial canker and blight.

Wait until February or March when the worst frosts are past. Winter wounds made in mild weather will open again in the next frost. In February pruning works better because your tree is about to start growing. Exception: dangerous hanging branches (storm damage) you can remove now if you can do so safely. Nothing more.

Outside: what still grows?

December in Flanders and the Netherlands: temperature hovers around freezing. Ground freezes solid if groundwater is high. Snow insulates bulbs and perennials, so do not be tempted to sweep snow off, it protects your bulbs.

In the cold north nothing grows, in milder winters (around 5 degrees) a few evergreen shrubs grow slowly. Leaf growth stops, so feeding has no point. Do not feed your soil now, that makes shallow roots that freeze in frost.

Planning and sketching: your garden for next spring

December without growing work is your chance to design. Grab pencil and paper (or your favourite design tool) and sketch your garden for next spring. What does not work? Which colour did you miss? Do you wonder if that peony fits on that spot?

In January you normally sow your first warmth-loving vegetables, in February you start sowing flower seeds. If you order your thoughts now, you already know what to do in January. Not sure if a plant suits that spot? On gardenworld.app you see it first in a preview of your own garden.

Step by step

Step 1: Health check for tender plants

Check container plants for dry leaves, mealy bugs and red spider mite. Tender plants you notice are sick, place them separately in quarantine. Sick plants brought indoors spread pests.

Step 2: Apply mulch layer

Lay 5-8 cm of mulch round perennials and shrubs. This insulates roots against frost. Mulch can be compost, wood chips or straw. Keep it 10 cm away from trunks, or stems rot.

Step 3: Prepare hessian and evergreen branches

Do you have Mediterranean plants? Set out hessian, green spruce branches and long ties. Do not wait until frost arrives, then it does not work well. Apply cover now, before 20 December.

Step 4: Place bird feeders

Place feeders under shelters (branches, small roof) so birds feed safely. Check daily if feeders are clean and full. Set them so you can clean them easily.

Step 5: Clean your tools

Clean secateurs, saws and spades with water and brush. Dry everything thoroughly. Sharpen everything with a file or professionally. Store everything dry.

Step 6: Sketch your spring garden

Draw a first sketch of what you want to change next year. Note colour schemes, plants you want to try, and beds you want to redesign.

Frequently asked questions

Can I plant winter pansies in December? Yes, winter pansies (Viola cornuta cultivars) tolerate frost to -10 degrees. They bloom on and off in mild spells. Plant them early December, not late. They need two weeks to establish roots before hard frost.

My Christmas tree sheds needles indoors. Should I put it outside? Needle drop indoors usually means the air is too dry, often from central heating. Move it outside only after Epiphany, not before. Put it first in a cool shed for a month so it adjusts gradually.

How many birds do I support by feeding? Each feeder attracts four to six regular birds. Large feeders with nuts and peanuts attract nuthatches, small feeders with small seeds attract blue tits. Expect dozens of birds in a medium garden each winter.

What temperature does my tender plant need indoors? Mediterranean tender plants (olive, oleander, myrtle) survive around 5 degrees, but grow better at 8-10 degrees. Tropical plants (citrus, angel's trumpet or Brugmansia) want around 15 degrees. Too warm (above 20 degrees) and they keep growing on scarce winter light, which produces weak, leggy shoots.

See it in your own garden first

Upload a photo of your garden on gardenworld.app and see a free preview design with hardy plants or bird-friendly plants in your own space. The high-resolution image with plant list costs 7,99, one time, no subscription.