December is the start of winter proper, that time of year when the garden’s stripped to its bare bones. It’s therefore the ideal time to look at the garden as a whole and plan both major changes and minor tweaks for the year to come.
There’s still a fair bit to be done. The period between Xmas and New Year is when many of us get the chance to clear the head and catch up with seasonal tasks put aside over the past few weeks.
Despite this, even the hardiest amongst us can be driven indoors if the weather turns bleak. If so, take time to browse through seed catalogues and start planning for the new growing season.
Lastly, make sure to enjoy those wonderful mornings when Jack Frost sprinkles his magic across the garden, taking solace in the fact that after the shortest day, the steady march to springtime is underway.
Happy Christmas and Happy Gardening!
Cut back Hellebores
Towards the end of the month, cut back all foliage of Christmas & Lenten roses. It may appear a little brutal but clearing away the tatty old leaves will show off the emerging blooms so much better, as well as limiting the spread of Hellebore leaf spot on the new leaves. Cut foliage away carefully so as not to damage emerging flower buds.
Pinch out Sweet Peas
When autumn sowings have put on 3 or 4 leaves. Gently nip out the growing tip above a pair of leaves to encourage strong, bushy growth lower down. Keep the compost slightly damp in a coldframe or unheated greenhouse.
Check on Dahlias/Cannas
Lifted last month. Cut out any tubers/rhizomes showing signs of rot. Dust cuts with sulphur and put back into storage in a dry, frost-free place.
Finish planting Tulips and Alliums
All other spring flowering bulbs should now be in, and the last of the Tulips and Alliums should be planted by the end of the month to get roots down before the cold stuff really starts. Late plantings will simply result in slightly later flowering come spring.
Pot up root cuttings
Well rooted cuttings of Verbascum, Acanthus, Phlox and so on can be potted up into 7cm pots of gritty compost. Keep undercover, ideally providing a little bottom heat if you have access to it.
Plant Lily of the Valley bulbs
Covallaria majalis is a marvellous bulb for naturalising in shady, slightly damp borders. Plant bulbs shallowly over the next couple of months to flower in late spring.
Order summer bedding
Mail order companies will now be taking orders for plug plants to be in delivered in spring. Shelter indoors on a cold day and put your feet up, dreaming all-the-while of a long hot summer, admittedly, still some time away!
Plant lily bulbs in pots
Plant bulbs deeply in pots of multipurpose before placing in a sheltered spot or coldframe.
Trees and shrubs
Cut sprigs for indoor decoration
Many shrubs have attractive berries at this time of year – Pyracantha, Cotoneaster, Ruscus aculeatus, Ilex, as well as Ivy and Mistletoe. Harvest foliage and berries from across to the garden to make a wreath for the front door or garden gate. Cut young stems of Hazel or Willow to make the hoop.
The first choice to make is a cut tree or a containerised one? Then, a non-drop tree or a more traditional specimen? Personally, I don’t think you can beat the Norway Spruce for it’s scent and sense of tradition. ‘Non-drops’ are more expensive but look impressive, albeit without the scent - the Norman Fir and Noble Fir are good bets.
With cut trees, pop straight into a bucket of water in the garden if you’re not planning to dress it straight away. When bringing into the house, saw a couple of inches off the bottom first to improve water uptake, keep well watered at all times and keep away from radiators/fires. Consider buying an antitranspirant spray to stop your tree dropping its needles before the big day.
Take hardwood cuttings
Many shrubs can be propagated via this method in winter. Take pencil-thick, 20-30cm long cuttings of Syringa, Cornus, Salix, Rosa, Forsythia, Hydrangea, Eleagnus etc. Cut below a node at the bottom with a straight cut and above a node with a diagonal cut for the top of the cutting. Apply rooting compound to the base and insert into pots of well-drained compost to set aside in a sheltered spot. Alternatively, insert several cuttings into a trench lined with horticultural sand in a nursery bed. Keep well watered and don’t be tempted to lift until next autumn at the earliest, even if they begin to show signs of top growth, as they’ll need to develop strong root systems before potting on.
Continue planting bare-rooted trees and shrubs. Soak overnight prior to planting and prepare the chosen site thoroughly in advance. Treat to plenty of organic matter both in the planting hole and as a mulch. Avoid any planting if the ground is waterlogged or frozen and check recently planted specimens to see they haven’t been lifted by frosts.
Prune out reverted shoots
On evergreen shrubs such as Eleagnus, Aucuba, Euonymus and Ilex. Reverted shoots will out-compete variegated stems and spoil the shrubs overall appearance.
Away from the base of trees/shrubs such as Syringa, Malus, Prunus etc.
Both ornamental and fruiting vines should be pruned this month to avoid inevitable bleeding from cuts made later on. Remove the very oldest/tired stems, tying in replacement shoots or ‘rods’ as horizontally as possible. Cut back all sub-laterals to 2-3 buds from the main framework.
Check tree ties
Strong winds may uproot new plantings, so check all ties are firmly in place. Ensure ties aren’t overly tight on those that have been in place for some time. Put tree guards around trees/shrubs threatened by damage from rabbits/deer.
Continue winter digging
As per last month. Do so on a dry day to avoid compacting the soil, leaving clods on the surface for frosts to break down. Incorporate as much organic matter as you can lay your hands on, removing all traces of perennial weeds such as ground elder, couch and bindweed whilst plots are relatively clear. Cover vacant ground where possible to protect soil structure & inhibit weed growth.
Always pick from the bottom up, either cutting sprouts away or snapping off from the stem. Remove yellowing foliage from all brassicas to negate the spread of disease, treat whitefly if necessary. Ensure Brussels are well staked and earthed up if you’re on an exposed site to stop them blowing over in strong winds.
Harvest kale, pick parsnips as required.
Crops such as oriental salads, broad beans and peas will put on little growth now but will soon perk up again in spring if seen through the next couple of months.
To stop pigeons stripping otherwise healthy plants of their foliage. At the very least hang up old CD’s on lengths of wire/string to act as a deterrent.
Force sea kale & chicory
Place an upturned bucket over clumps to bring forward early harvests. Chicons in particular are a delicious treat over the next couple of months when the vegetable garden is offering precious little else.
Start a compost trench
Perfect for climbing beans, peas and sweet peas. Dig a trench a couple of spits deep where spring-grown crops are to be sited. Fill with kitchen waste over the next few months, covering from time to time with layers of old newspaper and a little soil to dissuade vermin. By spring, it’ll act as a reservoir and release all that goodness those hungry legumes will thrive upon.
Check stored crops
Keep an eye on root crops and discard any showing signs of decay to stop it spreading.
Plan for the coming year
Crop rotation is a simple yet vital part of growing vegetables successfully. Take a little time to draw a simple plan of what’s to go where in the spring. I keep mine year on year to act as reminder - rotating the four basic vegetable groups each year helps stop the build up of pests and diseases and ensures the same nutrients aren’t continuously taken from the same spot.
Take hardwood cuttings of soft fruit such as gooseberries and currants. See advice in Trees and Shrubs and repeat as per that.
Bring pot grown peaches/nectarines undercover
As well as citrus trees and olives. Ensure all remain frost-free until spring and look to reduce watering.
Start pruning top fruit
The main winter pruning regime should be completed from now until March. Winter pruning of apples and pears is mostly about control – look to create an open framework by removing crossing branches, as well as dead, diseased or damaged growth. Avoid pruning too hard as this may encourage over-vigorous growth at the expense of fruit next year.
As a general rule, look to reduce last year’s growth by half to a third in order to encourage fruiting spurs. Shred prunings and compost if possible. Leave stone fruit, including plums, until summer. Consider investing in a pruning guide if you’re unsure as to pruning methods – the RHS’ guide to pruning is an excellent point of reference to gardeners of all abilities, mine’s certainly well-thumbed!
Deal with woolly aphid
This unsightly pest is best treated in winter. Either tackle with a suitable insecticide or spray off with a pressure washer. Use a stiff brush to remove from crevices.
Check stored fruit
Dispose of any showing signs of rot as it can quickly spread to neighbouring fruits.
Plant bare-root fruit trees/bushes
Avoid doing so if the ground is frozen, always preparing the soil thoroughly in advance of planting. Avoid planting grafted specimens too deeply as the graft can easily rot off and cause the plant to fail.
Avoid walking on frosted lawns
If at all possible as it can kill the blade tips, causing unsightly brown patches which may not recover again until spring. Work from boards if tending to adjacent beds/borders.
Book the mower in for a service
Dealers will be quieter now than in a few months time. If nothing else, check the oil and clean the air filter and spark plugs. Drain the petrol if your mower’s put away for any length of time.
Remove and store pumps for winter
Thereafter, if you’ve already cut back the old foliage on marginals, the pond can now be left for a couple of months aside from ensuring it doesn’t fully freeze over (more next month). Netting can now be removed and the leaves atop composted.
Bring potted herbs undercover
Such as parsley and chives. Cut back straggly growth and keep watered in a coldframe, greenhouse or porch/conservatory.
Place cloches over tender herbs
Such as tarragon. Lemon verbena is best lifted and brought undercover.
Undertake both minor and major landscaping tasks now so that everything’s completed and ready for spring. If you’re getting help, get quotes upfront and ask to see references/other work undertaken. Landscapers may be quieter than normal at this time of year, and it’ll cause minimal disturbance to the garden as a whole if you get that new patio, raised veggie beds, water features and the like completed now.
Clear out the shed
If yours is anything like mine, it’ll need a good sort and now is as good a time as any. Invest in/build tool racks to maximise space and whilst at it, check the roof and repair any leaks. Put down traps for rodents, particularly if crops are stored inside.
Turn compost heap
The perfect job on a cold day, or to clear the head and lose a few calories post Xmas! It’ll speed up the overall process appreciably by mixing the colder, less rotted material on the outside into the centre, as well as incorporating much needed oxygen.
To stop leaves and debris blocking down pipes and getting into water butts. Cover the ends of pipes with mesh or an old pair of tights to act as a makeshift filter.
Clean moss and algae from paths and patios
Use a pressure washer for large areas, or a bucket of hot soapy water, a stiff brush and plenty of elbow grease for those more manageable spots.
Protect worm bins from frosts
Bring bins undercover or wrap with bubble wrap.
Clean out seed trays and pots
Use hot water and a mild detergent to rid any lingering traces of pests and diseases. The seed sowing frenzy is only a couple of months away!
Protect pots from frosts
Particularly glazed and ceramic ones. Wrap terracotta pots with bubble wrap or hessian for extra protection. Empty any idle pots of old compost as if wet it can expand when frozen and cause the pot to crack.
Turn off taps
As per last month if you’ve not already done so. Lag outdoor taps and pipes after draining fully. It’s a quick and easy job that might avoid a nasty headache come spring.
Winter is a great time to tackle ivy clambering up trees and walls. Thick old stems are best cut and left for a few weeks so that it’s then more easily pulled away. Avoid putting ivy on the compost heap as it roots easily. Treat severe infestations with a strong herbicide, reapplying in spring if required.
Manage the greenhouse
Invest in a thermometer and pay closer attention to the environment itself. Open vents on mild days, at the same time keeping temperatures up via heating on cold nights.
Treat hand tools to some TLC
Scrub tools such as spades, forks and hoes with hot soapy water, dry and wipe clean with an oily rag. Sharpen pocket knives, secateurs and shears.