A particular cardboard box has been part of my Christmas ever since I can remember. It's about 25cm/10in square and once held a gas mask. Inside are a collection of old glass baubles: a bluebird hanging from a fraying bit of blue ribbon, a magenta teardop on a very long stem, with a crinkly bit of tinsel round the inlaid centre. There's a small bird house, iridescently pearly and a bunch of purple glass grapes, bound together on a beaded stem.
They were even older than my parents, these things. My mother said she'd been given them by an elderly couple, childless, Viennese I think, whom she had met at a language class. Between Christmases, the decorations sat in their gasmask box, wrapped in pages of the Radio Times December 1947 and it was part of the ritual that, each year, we packed them away in the same torn squares of paper.
Ritual is a vital part of Christmas, but when you move from one house to another, some things have to change. We can still hang a wreath on the front door of our new place, as we did on the old, but where should the Christmas tree go? More importantly, where should we put Father Christmas? Father Christmas is a cardboard mobile – him, the sledge and several reindeer – and he came to us in the Seventies, a spin-off from the brilliant strip cartoon books that Raymond Briggs brought out then.
In the old house, the mobile hung from a bacon hook in the ceiling of the back sitting room, high enough not to tangle in anyone's hair. Setting him in place was always the last thing we did, the finishing touch to our Christmas preparations. But we don't have such generous ceilings now and FC still hasn't found a comfortable place to fly.
Another change came when we shifted the Christmas feast from lunchtime to evening. That's only possible as your children get older. But gradually, the feast became the high point of Christmas, with anything from a dozen to 20 people around the table and because of that, I started another ritual. On the afternoon of Christmas Eve, I shut myself in the dining room and constructed a centrepiece for the table while listening to the King's College carols on the radio. When it was done, I shut the door on the room and nobody went in until Christmas night, when it was time for the feast to begin.
Flower arranging in the formal sense – pedestals, wafty bits of chiffon – is not my thing. But I love decorating and a centrepiece for the Christmas table gives more scope for invention than a Christmas tree. The transient nature of a table decoration is a huge advantage, too. You don't have to worry about what it may look like the next day. This is a one-night stand.
A Christmas centrepiece needs evergreens and things that shine silver and gold. It needs the warmth of red, but the red shouldn't come from roses. They feel all wrong at Christmas – ludicrously out of season, and therefore ludicrously expensive. Amaryllis (hippeastrums as they are now called) are in season and come in some wonderfully uncompromising shades of red. But they are tall, and you don't want to make a fence between one side of the table and another.
You can use them in a kind of cornucopia, though. Start with a big square of silver foil to protect the table and reflect light. Build up a bed of moss on that and lay a nest of terracotta pots (old ones if you've got them) on their sides in the centre, not tightly packed, but curving slightly one away from the other. Stand small pots of cyclamen here and there around the central pots and then construct a flow of twigs and greenery spiked with flowers to come from the mouth of the last pot.
It's an imprecise craft. But you do need a good supply of materials – most of which I usually get from the garden. Moss, twigs (especially beech and dark red twiggy bits cut from a variegated dogwood), teasels,f silvered seedheads are all good. Walnuts can be fantastic. Silvered, each one becomes a priceless artefact, the slight wrinkles of the shell looking as if they have been chiselled by a craftsman. If you are ultra-fashionable, you can turn out distressed walnuts. Spray them first with gold, them give them a quick burst of deep red, but not so much that it stops the gold shining through.
Ivy is the greatest of all gifts for decorating because at this season it carries heads of berry as well as strong, handsome evergreen leaves. As with the cyclamen above, ivy (sprayed or left green – it depends what you are using it with) disguises plastic pots, bridges awkward gaps, always drapes itself well wherever you put it.
Ivy is what I mostly use to make garlands as it's much kinder on the hands than holly. Start with a string of Oasis-foam sausages. You can buy special plastic cages, about 15cm/6in long, which split open to take a slab of the Oasis and then link together with hooks. Or, a cheaper option, you can wrap long, thin slabs of Oasis in plastic netting, pinching in the gaps between the slabs as you go. Make up the length of sausages you need, soak them in the sink until the Oasis is saturated and then let it drain.
Lay the whole thing out on a flat surface and start pushing short pieces of ivy into the Oasis. It covers up very quickly. You can add baubles or kumquats on wire, hips, dried orange slices (if you've had the forethought to make them), small sprays of silvered larch cones, bows of red velvet ribbon… but generally garlands look best if you stick to one evergreen for the background (it could be blue-green spruce, if you've got one you can cut) and no more than three add-ons. Tie string either end and fix the garland in place. I find they usually hang well, but if there are gaps in the chain, when it's in situ you can easily fill them with more greenery.
In any scenario around Christmas, candles are vital. The ones that are made from rolled sheets of beeswax look pretty and smell hauntingly of honey, but they don't last long, and will probably give up around the time of the Christmas pudding. Fat candles balance better than thin ones and enhance the sense of plenty that you should be aiming at. Creamy church candles are excellent and will last for several Christmases. I buy vast quantities from Ethos Candles factory shop, just off the A303 at Mere in Wiltshire (01747 860960). Happy Christmas.