December is a magical month in the garden. A blanket of snow is a sight to behold, the tiny blooms of winter-flowering shrubs can fill the air with fragrance and we’re spoilt for choice with cheery flowers that fill homes with colour and scent over the festive period. Here is our guide to the essential December gardening jobs this month.
Care for Poinsettias
Many a Christmas card depicts a beautiful red-topped poinsettia sat beside a roaring fire. In reality, this would finish your poinsettia flower off fast. While plants need warmth and light, they dislike temperatures above 20ºC and won’t thank you if the mercury dips below 15ºC (poinsettias also sulk by shedding their leaves if exposed to draughts). Keep their compost on the dry side, and only water when the surface has started to dry out because poinsettia plants hate sitting with their feet in the wet.
Avoid Snow Damage
There’s no finer mid-winter scene than snow carpeting the garden. In most cases, snow is harmless, insulating plants from biting winds and frost. However, use a soft broom to gently sweep heavy deposits from roofs of greenhouses and polytunnels, to prevent damage under the weight. Carefully shake the snow from branches of hedges and vulnerable shrubs to prevent them from snapping, and don’t walk on snow-covered lawns or you risk damaging the grass. When spreading salt to keep paths ice-free, ensure the salt doesn’t drift onto lawns or borders, as it can kill grass and foliage. Lag outdoor taps or turn them off if an isolator is fitted, to prevent pipes from freezing then bursting during a thaw.
Although amaryllis are often planted in autumn, so their towering spikes of showy flowers are in bloom for Christmas, many gardeners also receive these giant bulbs in gift boxes as festive presents. Plant into a pot of multipurpose or John Innes No2 compost, so that the top third of the flower bulb remains visible – don’t bury it. Water lightly, place in a bright spot at around 20ºC and it should be in flower in six to 10 weeks. Be aware that flower spikes can become top-heavy when laden with blooms and may require staking.
Plan a Winter Border
Do your borders look bleak in mid-winter? Then plan next year’s planting to introduce shrubs that will bloom in the coldest days, while some will fill the air with fragrance. Wintersweet (Chimonanthus praecox) loves a sunny spot and will reward you with spicy scent from its waxy yellow flowers. Viburnum x bodnantense ‘Dawn’ is another midwinter wonder, bearing small but highly fragrant pink flowers, while witch hazel is a showstopper (try Hamamelis x intermedia ‘Pallida’ for fragrant, wavy, sulphur-yellow blooms). The dazzling stems of dogwood are unbeatable for fiery colours – grow Cornus sanguinea ‘Midwinter Fire’ for its vibrant flame-coloured stems.
Harvest Winter Vegetables
A well-planned winter vegetable plot can yield tasty treats for your Christmas lunch, and brussels sprouts actually taste more flavoursome if they have been exposed to frost. Choose the firmest, tightly closed sprouts (usually towards the base of the plant) and snap them off with a quick downward pull. Winter cabbage, leeks and parsnips can be harvested for your festive feast, too. Where brassicas are still cropping, cut off yellowing foliage which can harbour pests and diseases. Keep brassicas covered by netting to deter hungry pigeons.
Give House Plants TLC
House plants crave light over winter, so move them to bright rooms, but never leave plants behind closed curtains on freezing winter nights, because temperatures can plummet and cause harm. Keep leaves free of dust by wiping them with a damp cloth and water sparingly – overwatering is the biggest killer of house plants in winter! Most house plants dislike the dry atmosphere of centrally heated homes during winter, so mist regularly with tepid tap water. Standing plant pots on trays of damp gravel can help to raise humidity.
With December being a quieter month in the garden, it’s an ideal time to carry out routine maintenance. If your lawn mower has been put away caked in grass, give it a thorough clean and sharpen the blade (your nearest STIHL approved dealer can do this for you if you’re not sure of the best way to do this). If it’s an electric lawn mower, check the cable for damage. Use a stiff brush to remove soil from tools such as spades and forks, then clean using a rag and WD-40. Sharpen blades on secateurs, shears and axes – the 3-in-1 sharpening tool is a handy option for this. Sludge can build up in water butts, so it’s a good time to drain them down and use the hose to thoroughly clean butts out, before reconnecting to downpipes. They’ll quickly refill from winter rain. December is also a good month for tidying sheds.
Prevent Ponds Freezing
Coldwater fish are tough cookies and can survive brief spells under a layer of ice, but it’s advisable to keep an area of the pond ice-free as aquatic wildlife needs oxygen. A good method is to float a football or two on the surface before temperatures dip – as the balls move about in the breeze they hinder the formation of ice. If the pond does freeze over, place a saucepan of hot water on the surface to melt the ice and provide a breathing hole. Never smash the ice with a tool or hammer because the shockwaves can harm or kill fish.
Buy a Real Christmas Tree
Choosing a Christmas tree marks the start of the festivities. Instead of buying a cut tree that’ll be recycled in January, why not invest in a potted tree that can be planted in the garden in the New Year or kept in a big container to bring indoors year after year? Potted trees can be a bit more expensive, but they’ll drop fewer needles, and a living Norway spruce will fill the house with a wonderful Christmassy pine fragrance. Keep living trees well-watered, stand them away from radiators and put trees out in the garden promptly when the decorations come down.
Order Seed Catalogues
When the ground lies frozen and it’s dark by 4pm, there’s nothing like sitting by the fire, browsing seed catalogues and planning next summer’s displays. Order seed catalogues now and you’ll be in pole position to send off for your chosen flowers and vegetables early in the New Year, when seed supplies are plentiful. UK gardeners are spoilt for choice: Thompson & Morgan, Suttons, Mr Fothergill’s, Unwins, Chiltern Seeds, Kings Seeds and Plant World Seeds are just a handful of must haves for seed growers. Most seed suppliers have their full range available to browse online, too.
Do you have any other gardening jobs you complete in December? Let us know in the comments!
Marc Rosenberg bio
Marc Rosenberg is a freelance garden writer and editor. A former journalist with Amateur Gardening and Horticulture Week magazines, he holds seven Garden Media Guild Awards. Marc has written for publications including The Garden magazine, BBC Gardeners’ World and RHS online.