Mulching the base of larger trees or moving smaller species indoors will help them to survive winter
The December garden is a tranquil one — a welcome retreat from the hurly burly of the run-up to Christmas. Deciduous trees have mostly shed their leaves and herbaceous plants are dying back. Squirrels race busily to collect their bounty, and a robin hops impatiently, waiting for the gardener to fork over some earth and reveal some juicy worms.
There are still treasures. Some roses are valiantly blossoming until the last moment and ornamental grasses shimmer gold when the low winter light catches them. A flash of violet in the undergrowth reveals the flower spikes of Liriope muscari — a great ground cover for partial or full shade.
Fatsia japonica looks its best at this time of year, sending up white candelabras of small white flowers arranged in small globes. These can be cut and dried for indoor seasonal decorations. Go foraging in your garden and see what you can gather in the way of attractive greenery, berries and branches that can be kept fresh in a bucket of water or sprayed silver, gold or white for Christmas wreaths and gifts.
If you’re not too busy shopping or just want to escape the mayhem, there are some gardening jobs to be tackled as well. There’s always plenty of cleaning up to do around this time of year — clearing leaves, weeding and cutting back dead perennials. But don’t be tempted to cut flower heads on hydrangeas. Leave them be as this will provide some frost protection to the developing buds in spring.
Winter is a good time to improve your soil structure by gently forking in compost or manure, allowing time for the worms to break down the organic matter, making your soil rich and ready for next year. Weedy patches can benefit from the no-dig approach at this time of year. Cover the area in layers of cardboard and mulch over with bark. The cardboard will decompose, and excluding light from the weeds will get rid of them over winter. By not digging them up, you are protecting the precious soil structure. With temperatures plummeting, make sure tender plants are either wrapped up or indoors. The simplest method is to bring your plants indoors into a conservatory or simple greenhouse. Even an open veranda or close to the eaves of the house will provide some protection. Some of your tender plants will go dormant in the winter and can be lifted for overwintering — for example, cannas, dahlias, gladioli and begonias.
This isn’t practical with larger tender plants such as bananas, olives, palms, bay trees, cordylines, echiums, gingers and tree ferns. If you can’t bring them indoors and need to protect them in situ, there are a variety of ways to do so. Mulching around the base will help any plant, tender or not, to survive the winter months. This can be with straw, mulch, dead leaves or compost. You can also cover with horticultural fleece or polythene. Individual smaller species can be protected with cloches, and the larger species can be wrapped in hessian or even bubble wrap.
One of the things I am most frequently asked about is how I look after my tree ferns in winter. Living near the coast, they don’t experience heavy frost and have survived a couple of days of snow in years gone by. But if you’re in a colder area, mulch the crown with straw or hessian and that will help.
If it’s cold outdoors, it’s fun to browse through seed catalogues and dream of what you might grow next year. It’s convenient to pick up packets in your local garden centre or supermarket. However, if you are hunting out something more unusual, you may need to order online or by post. Even if you’re not thinking about buying, just reading about and exploring what’s available is a great way to learn about different varieties and species.
Clematis cirrhosa is an evergreen winter flowering type and has scented bell-shaped creamy-white flowers. The should be grown in a warm sheltered position in fertile, well-drained soil and in sun or light shade.
QI love hydrangeas and would like to propagate some but know nothing about this. Do I take cuttings now or wait until spring? Is it better to take cuttings down at the bottom of the existing plant or at the top? Is it better to take cuttings below the leaf or above? What compost should I use? Do I water them in a pot or the ground?
A Hydrangeas grow very well from cuttings, and you can do this in summer with softwood or semi-ripe cuttings or now with hardwood cuttings. In all cases, you cut a robust-looking non-flowering shoot, about six inches in length for hardwood. You cut just below a leaf node, which is where you will find the greatest concentration of growth hormones. A gritty compost is best — ground or pot is fine for hardwood — and keep them watered.
Submit your gardening questions to Diarmuid via his Instagram @diarmuidgavin using the hashtag #weekendgarden