What to plant in December

December planting at a glance

December planting: the short version

Job	What the RHS says
Hedging and trees	Carry on planting bare-root deciduous hedging and trees, unless the ground is frozen or soggy.
Roses	Plant them, preferably bare root.
Garlic and shallots	The one vegetable planting job: in mild areas with well-drained soil.
Seed	Sow alpines. They need the cold to break dormancy.
Cuttings	Take root cuttings from perennial poppies, mullein and phlox.
Pruning	Hold off on hydrangeas until March. Leave Prunus, such as ornamental cherries and plums, until spring.
Protection	Firm back any roots that frost has lifted, mulch with straw or composted bark, and raise pots onto feet.

In the ground now

The RHS's December advice for trees and shrubs is short. Carry on planting bare-root deciduous hedging and trees. Plant roses, preferably bare root.

Established deciduous trees and shrubs can be moved if the ground isn't frozen or soggy.

The same rule runs through the month's fruit advice: plant new trees and bushes, but not if the ground is waterlogged or frozen.

Garlic and shallots

There's one vegetable planting job in December: shallots and garlic, in mild areas with well-drained soil. That's all. The RHS lists no vegetable sowing for the month, and its seed-sowing guide treats December and January as the time to plan. Our vegetable planting calendar shows what comes next, month by month.

Seed and cuttings

You can sow alpines from seed this month, because they need a period of cold to break dormancy. Lay a sheet of glass over the sown area to keep off excess wet, or stratify the seeds in the fridge for sowing next spring. Root cuttings can be taken from now, from perennial poppies, mullein and phlox.

Plants for winter stems

One job is for next year. When you visit gardens and garden centres, note the most colourful dogwood, willow and white-stemmed Rubus, and consider planting some for a winter display.

For flowers in December itself, the RHS winter interest list gives Hamamelis × intermedia and Helleborus niger from December to March. It gives Clematis cirrhosa from November to March. Daffodils sometimes come up before Christmas, too.

Beds, bulbs and hellebores

Faded herbaceous perennials give you a choice: cut them back and compost them, or leave them until spring as winter homes for insects. In mild areas, and during dry spells, you can still lift and divide perennials, which increases your stock and revives tired clumps. If you've forced bulbs in the dark, check them. When there's top growth and a healthy root system, bring them into a cool, light room to flower.

Christmas roses need a little help. The blooms of Helleborus niger can look unsightly when splashed with muddy rain. A mulch of bark chips reduces the splash, with cloches where practical. For winter pieces on the wall, see our Christmas gifts for gardeners.

Look after what's gone in

Frost does odd things to new planting. Cold winds and frost can loosen and lift the roots of trees, hedges and shrubs planted this year. If you notice it, firm them back in gently. A thick, dry mulch of straw or composted bark insulates the roots, and a quick check of ties and stakes is worth doing.

Check that tender plants outdoors still have their winter protection, especially after storms. Raise pots onto feet or bricks so they don't sit in the winter wet. Wrap large tubs that might crack in the frost with bubblewrap, hessian or fleece.

What to leave alone

Not everything should be cut now. Hold off on pruning hydrangeas until March, because the old flowerheads help protect the shoots from frost. Evergreens, tender plants and Prunus such as ornamental cherries and plums are better left until spring. They're vulnerable to silver leaf if pruned in autumn or winter. Many deciduous shrubs and hedges, such as beech, hazel and hornbeam, can be pruned from now through the dormant season. Open-grown apples and pears can be pruned too, but not those trained against walls. When to prune apple trees has the detail.

Planning for spring

Two jobs suit the dead of winter. Order seed catalogues now, because you're more likely to find everything in stock if you order well before spring. And work plenty of bulky organic matter, such as composted bark, into heavy clay to improve its drainage.

Christmas, indoors and out

If you're also buying plants to bring inside, see our guides to poinsettia, amaryllis and Christmas cactus care. The tree needs care too. The RHS calls Norway spruce the traditional tree, with a good scent but quick to drop its needles. It describes Nordmann fir as very slow to drop them, though more expensive. Keep the tree away from a fire or radiator, which causes needle drop. Saw 2.5cm off the bottom, stand it in a well of water and check it daily. With care, a cut tree should last about four weeks. A potted tree should come indoors as late as possible, and the RHS suggests the weekend before Christmas. It should not stay in the house longer than 12 days. For gifts for the gardener, our Christmas gifts for gardeners are printed to order, and our November planting guide covers the month before.

A bare-root hedge looks like nothing when it goes in. Photograph the trench on the day, and again in summer. Upload your garden photo, and the free preview shows how an art style treats it.

Sources

• RHS: December jobs
• RHS: December, flowers
• RHS: December, trees and shrubs
• RHS: Grow your own, December
• RHS: Sowing seeds, vegetables
• RHS: Plants for winter interest
• RHS: Christmas trees, types and care