Here are your gardening jobs for the month – with added links if I have more information on the subject. They are all still relevant to do now if you’ve fallen behind or if the weather’s been bad.
Order summer-flowering bulbs and tubers now, such as gladioli, dahlias, and begonias from mail-order specialists if you want unusual varieties, or pop along to your nearest garden centre for more popular choices.
Check arches, fence posts and panels are secure after storms. Make sure the stakes on young trees are sound, and that climbing plants are securely fastened. Firm back newly planted trees and shrubs if they have been lifted by winds.
Sweet peas sown in autumn can be potted on. Place them on a sunny windowsill, or on a high shelf in the greenhouse in as light a situation as possible to prevent them from getting leggy. Watch out for aphid attack.
This is the last chance to sow seeds that need frost to germinate (native trees, shrubs and alpine plants, such as Sorbus, Cotoneaster, and Pernettya).
Don’t forget to check out independent garden centres and nursery sales – you might get a bargain!
Root cuttings can be taken now. Papaver (perennial poppies), Verbascum (mullein), Acanthus and Phlox are suitable.
Lift containers outside on to old bricks, to stop them sitting in the wet.
Watch out for overwintering pests in the greenhouse/conservatory. Nooks and crannies, and the bark of woody plants and vines are prime hiding places.
Clean old pots and seed trays, so that they are ready for sowing and planting.
Monitor the water level of ponds – frosts can damage liners and concrete. If the water level drops, it may have a leak. Keep it topped up until repairs can be carried out in spring. Rake out fallen leaves or shake off those that have gathered on protective netting.
Prune apple and pear trees – at least get rid of any branch that’s dead, damaged, diseased or rubbing on another one. Then spray your trees with winter wash or home-made garlic spray, which will kill insect eggs.
Mulch borders with leaf mould, compost, well-rotted manure, or even old grow bags, at least two inches thick.
Plant lily bulbs in pots and in borders during mild spells.
Cut off old leaves of hellebores that produce flowers from ground level so you can see them. Watch out for hellebore leaf spot.
Start cutting back grasses that have been left for winter structure – the winds will have battered them by now.
During dry, mild spells, you can still lift and divide herbaceous perennials.
Inspect stored tubers of dahlias and cannas. Too damp and they will rot, too dry and they will die.
Some pots outside under eaves or balconies may need watering. Keep them moist (not too wet), and don’t let them dry out.
Plant bare-root deciduous hedging, trees and roses, staking before planting, so you don’t damage the rootball.
Move deciduous trees and shrubs, if the ground is not frozen or waterlogged.
Indoor forced bulbs for Christmas displays, which have finished flowering, can be left outside in a sheltered spot, to die down.
In a cold snap, place floats on the surface of ponds to keep them from freezing over – this can be fatal for fish and pond life. To make a hole in frozen ponds, hold a saucepan of hot water on the surface until melted through. Do NOT crack the ice.
If there is heavy snow, brush shrubs and conifers gently with a broom to prevent branches from getting damaged. Packing the branches of borderline hardy deciduous trees and shrubs with straw and securing this with fleece and ties, will protect them from frost.
Snowdrops can be lifted and divided as long as you re-plant them straight away.
Make sure protective straw or fleece is still in place on vulnerable plants overwintering outdoors. In cold spells, protect non-frost-proof containers with bubble wrap, hessian or fleece. Group pots near a south-facing wall to give extra protection.
Take hardwood cuttings of shrubs such as Cornus, Salix, Forsythia, Weigela, Escallonia, Rosa, Ribes, Chaenomeles and Elaeagnus and deciduous climbers such as Fallopia and Lonicera. Check last year’s hardwood cuttings, for planting out or potting on.
Phytophthora root rots can cause dieback on mature trees and shrubs. Wet winter weather and poorly drained soils will make the likelihood worse on susceptible woody plants.
Bracket fungus on trees is often noticed this month – if the tree is suffering, call in a tree surgeon.
If your Christmas cactus (Schlumbergera truncata and S. x buckleyi) didn’t set flower buds, it may be that the temperature was too high (above 18°C/65°F, or had too much artificial light. Move it into cooler conditions away from night lighting. Encourage bushy growth by twisting off outer segments after flowering. These can be used as cuttings if dried and kept warm for a week before potting up.
Mole activity increases from now until February, due to mating and nest-building. Remove the largest hills from your lawn and firm before seeding it in spring.
Clear borders of wind-blown debris, dig out any leftover annuals and if they are really annoying you, cut herbaceous perennials down to their crowns. Look out for rotting on died-down perennials.
Prune late summer-flowering clematis. To keep your clematis small and to rejuvenate old plants, cut back hard to about a foot off the ground. if you want to keep them taller, just prune last year’s flowered shoots.
Clear alpine beds of debris and cover bare patches with gritty compost. Remove weeds before mulching in spring.
Keep containers tidy, cutting back and removing dead leaves. Mulch with grit – it looks good and reduces surface puddling after heavy rain.
Watch out for downy mildew and black spot on winter pansies. Remove infected leaves and destroy badly affected plants.
Prune Wisteria – cut back side shoots shortened by summer pruning to two or three buds. Don’t cut off flower buds!
Ornamental vines, ivy, Virginia creeper and Boston ivy can be cut back now – keep them away from windows, doors, gutters and roof tiles.
Coral spot is often noticed on twigs from deciduous hedges, shrubs, and trees, connected with poor ventilation and congested, twiggy growth inside clipped hedges.
Cacti need very little water, and no feeding, during winter. Keep them barely moist until spring.