Noel Kingsbury: How to make a bonfire that doubles as a spectacular natural firework display

Garden designer Noel Kingsbury on the joy of a good bonfire.

One of my childhood memories of being with my dad in the garden was bonfires. Back in the 1960s, this was how everyone got rid of garden ‘rubbish’. Hardly anyone had a compost heap and the council certainly did not do a green-waste collection. If you could not burn it, the only thing to do was to drive into the woods and dump it by the side of the road.

My father never did that, although we would often go into the woods to dig up leafmould to create nice humusy soil for his choicer plants. These were the days, too, when tree surgeons did not have noisy chipping machines, but piled all the debris into a big heap and lit a fire. Gardeners and council workmen, too, in sweeping up leaves in the autumn would pile them into great heaps and burn them, fumigating entire neighbourhoods.

Nowadays, bonfires are frowned upon and, in some European countries, such as Holland, they are illegal. In others, however, the tradition continues; I now live in central Portugal and, in October, everyone lights up and the valleys can fill with acrid smoke. Odd, for a country that has suffered terrible forest fires over recent years.

“Several kilos of hollow stem will ignite and practically explode skywards”

As a child, I learnt that there is a real art to a bonfire: start off with really dry wood, get it going, and only add other material slowly. Once it’s established with lots of red-hot wood at the base, you can add more or less anything and watch it burn.

Evergreens — holly or conifer branches — would flare and burn ferociously, but ‘green stuff’ — soggy, leafy branches or perennial stems — would take ages to dry out and ignite and would sit on top of the fire producing vast clouds of smoke. Eventually, however, I learnt that it, too, would begin to produce flames and begin to burn ‘properly’.

Bonfires were fun — especially for small boys — and sometimes they segued into social events, with friends throwing on branches, with resin-laden conifer branches especially appreciated.

Adults needed to restrain and ration the amount thrown on and, at times, the material. I have a very clear memory of a friend’s mother yelling at him not to throw one of the family chairs on to a blaze. As the fire died down, we would put potatoes in silver foil into the embers to bake, so we’d have something to eat before we were sent home.

The celebratory aspects of a good bonfire have deep origins, fires having always been a central part of human life and ritual. The ‘bon’ in the word comes not from ‘good’ but from ‘bone’, originating with the ancient Celts who burned animal bones as part of purification rituals.

Later, bonfires took on a sinister tone when used to burn heretics or forbidden literature, a past we relive every November. There is undeniably something deeply cathartic about a good bonfire, whether it is garden waste or a ‘guy’ that we set alight.

We used to complain about the smoke of the old garden bonfires, but accepted it as part of normal life. What else could you do with garden rubbish? It was organic gardening campaigner Lawrence D. Hills who made people aware of how bad these bonfires could be for our health, writing in Grow Your Own Fruit and Vegetables in 1971 about medical research that showed that bonfire smoke could contain 200 times more toxins than the cigarette smoke we were also then learning was so harmful.

It was the soggy leafy material that smoked so badly that was the real culprit, he said. Why not compost it instead? Why, he asked, were we destroying all that organic matter that could be improving our soil? And so composting was born, passionately indulged in by organic growers. Generations who came to gardening later find it hard to believe that hardly anybody back then kept a compost heap.

A variety of factors brought the demise of the garden bonfire. An awareness of air pollution and the start of council composting services, of course, but also the nature of gardening itself. The old-fashioned bonfire was based largely on burning woody material. Today’s gardens involve far more herbaceous perennials, the dead remains of which do not burn well and can get very soggy. Realistically, composting is the only suitable fate for such stuff.

There is one component of the modern garden that does burn well — ornamental grasses. In my previous garden, in Herefordshire, I would cut down all the perennials before Christmas, but leave the grasses standing until February and then, on a nice dry day, I would light a fire at the base of each one. Calamagrostis ‘Karl Foerster’ will flicker, flare and then throw flames three yards into the air for a spectacular 10 seconds.

Stipa tenuissima will flare and spit like a ground-level sparkler. Miscanthus grasses, if you can get them dry enough (a bit of an ‘if’ in a west-of-England winter) are veritable fireworks. Light some screwed-up paper at the base, stand well back and you will understand why they are grown for biomass, as several kilos of hollow stem ignite and practically explode skywards. Welcome to the ‘new perennial’ firework party.

Garden Flora: The Natural and Cultural History of the Plants in your Garden by Noel Kingsbury is out now.