By Ruth Hayes published
‘Tis the season to be jolly – but that’s no reason to neglect your December gardening jobs. In fact, it can be quite nice to get away from the festive hullabaloo and get some peace, quiet and exercise in your garden!
As long as the soil stays workable - not frozen or waterlogged - you can plant, move and divide perennials and continue planting trees and shrubs.
Other winter jobs in the garden include caring for plants overwintering undercover, maintaining your compost heap and, of course, scouring your gardens for greenery and bright berries to use as Christmas and Thanksgiving decorations.
And as the days are shortening and the weather is getting colder and damper, this is the perfect opportunity to go undercover and make sure your greenhouse and sheds are clean and tidy, too.
Keep your plot in shape with our top December gardening jobs
Our pick of December gardening jobs will help you create the garden you want and also keep plants healthy and flourishing.
1. Move perennials
Sometimes we make mistakes and plant things in the wrong place in our garden borders. If you have a perennial or two that aren’t thriving or look wrong and you have found perfect spots for them elsewhere, you still have time to get relocating.
Having said that, if the soil is frozen or waterlogged, leave them where they are and make the move next spring, just as they are coming back into growth.
Follow this method for moving perennials:
- Start by digging a new planting hole large enough to accommodate all the rootball, then add some bone meal to the base. This will degrade through winter and help feed the roots when the plant comes back into growth next spring.
- Carefully dig around the plant you want to move and lift it from the ground, keeping as much soil around the roots as possible.
- Move it straight to its new home and once it is in the hole, infill around the roots with soil and compost.
- Firm this soil down as you go so it falls around the roots, supports the plant and gets rid of air pockets, then water around the roots generously. Remove any weeds that grow around the plant and make sure the roots don’t dry out while it settles in.
If you feel you are in need of some new digging equipment and have an eye on potential Christmas gifts, our guide to the best garden spades is the best place to start your search.
Top tip: You can help prevent soil compaction by working off a plank or wooden board when planting and dividing.
2. Prepare hellebores for flowering
Hellebores, or Christmas/lenten roses, are one of the first perennials to come into flower in early spring. They are a beautiful and varied plant, happy in most soils and situations, though dappled shade is their favourite.
Their flowers, usually in shades of red, purple, cream and white, will start emerging through the soil in the New Year, so if you're learning how to grow hellebores, it's important to create ideal growing conditions for them to look their best.
For one of your December gardening jobs, start cutting away this year’s old and tattered foliage. This improves the plants’ appearance and also reduces the risk of diseases entering through damaged leaves.
Once the old leaves have gone this next generation has room to grow and you can further help the hellebores by mulching them with a thick layer of compost or well-rotted manure to feed the soil and insulate the roots through the worst of the winter weather.
If you haven’t already done so, cut back the rest of your perennials now to help keep plants healthy and beds looking neat.
Bundle dried hollow stems together and place them in a hedge or bush to create safe hibernation havens for insects and invertebrates and turn your garden into a wildlife garden sanctuary over the winter months.
Top tip: Don’t worry if remaining plant leaves are blackened by frost through the winter. Cut them off to make room for fresh new growth that will emerge next spring.
3. Tidy up tender perennials
Unless you are lucky enough to live somewhere warm, or your garden is sheltered, your tender perennials such as pelargoniums, fuchsias and dahlias should either be undercover or fleeced and mulched to help protect plants from winter.
Large pelargoniums should be cut back to between 4-6in (10-15cm). This helps keep them healthy through a winter undercover, when subdued lighting and reduced ventilation could potentially make their dense and fleshy foliage more vulnerable to diseases such as botrytis, a common grey mould.
It also helps prevent them from forming flower buds during mild spells of weather, because this will divert their energy away from root and stem development when they come back into growth, weakening the plant.
Don’t feed them through winter and only water occasionally when the compost has dried out.
What you can do, though, is use the offcuts as pelargonium cuttings. Here is what you do to take cuttings from plants:
- Start by stripping away their lower leaves and large top foliage.
- Then dip the cut end of the stems in hormone rooting compound to encourage strong root development.
- Insert the cuttings into pots of dampened gritty seed and cuttings compost.
- There is no need to cover the cuttings with a clear plastic bag, but do keep them in a light, frost-free place through winter – a frost-free greenhouse or cool, light windowsill indoors are ideal.
- Keep the compost damp and the cuttings should develop roots within a few weeks.
Top tip: Keep checking pelargonium cuttings for sap-sucking pests, such as aphids. that are drawn to their tender young leaves. Want to know how to get rid of aphids quickly? Either squish them with your fingers or spray with an organic pesticide.
4. Make your fig tree more productive
Although far more common in warmer climates, fig trees are now widely grown in the UK. If you're keen to learn how to grow figs, ‘Brown Turkey’ is generally seen as the easiest, and most popular, variety to cultivate.
I have a fig tree growing on a warm, south-facing wall and although it is only six years old, this year it gave me a glut of delicious, succulent fruit. However, because of the brevity of the British summer not all the figs ripened and these half-ready ones need to be removed now.
If you leave them they may start to rot, endangering the health of the tree and even if they stay healthy, they still won't ripen next year.
They are easy to take off, just give a gentle tug and then add them to the compost heap. Take them all off, leaving the minuscule fruit buds, barely larger than a small fingernail, in place.
These can be found in the joints where the leaves meet the branches, and they will sit out winter and swell and grow next summer.
Top tip: Fig trees are vigorous growers and need pruning – but not yet! Leave this job until the end of winter (around February), otherwise they will bleed profusely and lose too much sap.
5. Plant a shrub for winter scent and color
As long as the ground isn’t frozen or saturated, you can plant trees and shrubs as one of your December gardening jobs. In fact, you will be spoilt for choice as most varieties will be available to buy bare root, so they are smaller and considerably cheaper than those sold in containers.
Best of all, there is no need to wait until spring to see the results of your planting. If you choose a container-grown variety with evergreen leaves, scarlet berries, or one one of the best winter flowering shrubs, such as a Daphne odora, sweet box (Sarcococca confusa) or Viburnum x bodnantense 'Dawn', then you will have a pretty spectacle to greet visitors this festive season.
From a gardener’s point of view, early December planting requires less work because the ground is damp and easier to dig and the season means you shouldn’t need to water as often as in spring and summer.
Just make sure the tree or shrub you buy suits your soil, or a container if that’s what you are planning, and has enough room in the spot you wish to plant it.
Before planting, soak the pot in water (or soak the roots if it is bare root) and make sure the hole you have dug is large enough to accommodate the rootball comfortably. Add some bone meal to the planting hole, as this will break down through winter and feed the roots next spring,
Firm the soil down around the tree or shrub (or compost if it is in a garden planter) and water generously, even if rain is forecast.
Top tip: If you have heavy soil prone to waterlogging, create a shallow mound of soil and grit and plant your tree on that, adding lots of well-rotted compost or manure matter to improve fertility and boost drainage.
6. Keep your greenhouse clean
Greenhouses are busy places in winter, often packed with tender plants, cuttings and seedlings. They need to be kept well ventilated and pest-free and the glass should be clean to allow maximum light levels through to the plants within.
Disinfect surfaces too to avoid contaminating young plants or seedlings you grow and sow during winter.
On warmer days, open doors, windows and vents to let air pass through your greenhouse and help prevent fungal problems, moulds and rots attacking plants. Remember to close them in the afternoon when temperatures fall.
Another task to add to your December gardening jobs is to check for pests, especially snails and aphids that will happily seek shelter in a warm greenhouse.
Top tip: There are plenty of options for the best winter vegetables to grow in a greenhouse during the colder months. One of the easiest to try is cut-and-come-again salads in old growbags and containers to give you lots of fresh and vitamin-packed greens through winter.
7. Keep your compost ticking over
Keep adding prunings, green kitchen waste, grass clippings and dead plant material to your compost heap.
For the best composting results, chop up woody material so it breaks down faster and never add anything that is diseased, such as rose prunings infected with black spot.
If you are overwhelmed with cardboard delivery boxes this festive season, you can cut them up and add them to the heap as well.
Turn the contents of your compost heap regularly with a fork, taking care not to spear the contents too fiercely in case you injure any wildlife hibernating within.
Rain will help composted materials to decompose faster, especially if they are building up heat as they break down in the heap. However, if dry and very cold weather is forecast, cover the heap or plastic 'Dalek' bin with some old carpet. This helps retain moisture and heat and keeps things ticking over well.
Ever wondered about the difference between compost vs mulch and what is best for your garden? Our guide has all the answers.
Top tip: Never add cooked food or pet waste to your compost as it will attract vermin.
8. Get festive with garden plants
If you have a rooted Christmas tree growing in a container, it may need top dressing with fresh compost or re-potting altogether. Choose a pot one size larger than the one it is already in and use ericaceous compost.
If you plan to bring it indoors, wait until the last minute as pine trees don’t take kindly to hot, centrally heated interiors. For best results with how to keep a Christmas tree alive, place it away from radiators and open fires and return it outside as soon as you can.
Top tip: Save fallen pine needles and use them as a mulch around acid-loving plants such as blueberries, rhododendrons and azaleas.
9. Look after your lawn
The winter months are hard for our lawns and ideally we should walk on them as little as possible. This is especially true in freezing weather as footfall can flatten and kill the grass, leaving dead patches that are swiftly colonised by weeds and moss.
There are several things you can do as part of your December gardening jobs to keep it healthy so it is ready to grow again next spring.
Grass keeps growing as long as the temperature is above 41˚F (5˚C), so you can still use your lawn mower, though keep the blades high to avoid churning up the soil.
Areas of lawn with compacted soil can become waterlogged, so learn how to aerate a lawn by driving the prongs of a garden fork into the affected ground to improve airflow and help the water run away.
Another autumn and winter problem is the appearance of worm casts, slimy coils of mud that worms push up onto the surface of the grass. If trodden on they can become a host for weeds, moss and algae, so leave them to dry and then lightly brush them away. You can also use the back of a garden rake to disperse them.
Top tip: Areas on the lawn that are shaded or growing under trees and shrubs where there is little airflow can be vulnerable to fungal diseases such as red thread and fusarium patch. Improve airflow and light levels by pruning back overhanging branches and staying off these areas in winter.
10. Keep your shed tidy
Escape into the shed on dark, wet and dismal days and give it a good tidy for one of your December gardening jobs! If everything is in a jumble, with nothing in its right place, winter is the perfect time to organise some practical shed storage ideas for tools, pots and chemicals.
Sharpen and clean your tools and hang them up so they are easily accessible and the floor is clear. Not only do practical garden tool storage ideas make life easier, they will prevent you from buying duplicates of things you thought were ‘lost’, thus saving you money!
Make sure any garden chemicals are in their correct containers – never decant them into other bottles – and keep them out of the reach of children and pets.
Also ensure that pesticides and weedkillers are stored well apart – we have heard several horror stories from readers asking for help after they have used a weedkiller instead of a pesticide on their prized plants, with traumatic results.
Top tip: Go through your pots and trays, recycling those that are broken and washing those that are reusable. It will save money and also help save the planet.
Ruth is the gardening editor of Amateur Gardening magazine and spends her working days carrying out, writing about and photographing the tasks the readers should be carrying out each week, as well as testing many of the new products that arrive on the gardening market.
She is horticulturally trained, with a qualification from the Royal Horticultural Society, and her work varies with the seasons and includes everything from sowing and planting, to pruning, taking cuttings, dealing with pests and diseases and keeping houseplants healthy. She covers ornamental plants and edible crops and everything she writes about and photographs is in her own garden, a mature plot that has been a work in progress since her family moved to their current house in 2012.
Her main interests are gardening for wildlife and organic gardening, as she firmly believes you don’t need to ‘nuke’ pests and problems with toxic chemicals, nor use peat composts to produce the garden of your dreams.
Garden fence ideas: 27 ways to update your boundaries with panels, paint, and more
Ideas Freshen up your plot and add extra privacy with these garden fence ideas
By Sarah Warwick • Published
DIY greenhouse designs that will look amazing in your garden
Garden Buildings Nifty and thrifty inspiration for DIY greenhouse designs for growing perfect blooms and tasty vegetable crops
By Jill Morgan • Published