Elderflower

There is a moment, somewhere in the last week of May, when the lanes of Northern Europe seem to foam at the edges. You notice it without quite registering it at first — a froth of cream-white in the hedgerows, suspended on a shrub that nobody seems to have planted and nobody quite owns. Then the smell catches you: muscaty, honeyed, slightly feline if you put your nose too close, and unmistakably of a particular two weeks in the year.

Elderflower.

It is one of those ingredients that exists almost entirely outside the supermarket. You can buy the cordial in bottles, and you can sometimes find the dried flowers in a Polish grocery, but the flower itself — the umbel, that flat pale lacework of tiny stars — you have to go and find. Which is exactly why every culture that lives within a hedgerow of Sambucus nigrahas has its own private grammar of what to do with it once you have harvested some.

In Britain the answer is cordial. Always cordial. Recipes vary in their proportions of sugar and citric acid and bruised lemon, but the shape is identical: pour boiling syrup over thirty or so heads of flower in a clean bucket, leave it for a day or two, strain, bottle, and discover that you have made about four litres more than any reasonable household requires. The cordial then sits in the back of the fridge for the next eleven months, used a splash at a time in gin and tonics, in panna cotta, in the unanswerable English question of what to do with a glut of gooseberries — the answer being: cook them with elderflower, because the two ripen together and taste, together, like the inside of an early-summer afternoon.

Hugh Fearnley-Whittingstall popularised an even more reckless tradition, which is to make elderflower "champagne" — a wild-fermented fizz that requires no added yeast, only the natural cultures clinging to the flowers themselves. It is excellent. It is also, famously, prone to exploding in the night, which is why people who brew it tend to store the bottles in the bath, where the survivors can be filtered from the dead.

Cross the Channel and the logic changes. In the Tyrol and across rural Austria, the umbel is dipped in batter and dropped, whole, into hot oil — Holunderblütenküchel, the elderflower fritter, served with a dusting of icing sugar and, if you are very lucky, a small spoonful of stewed rhubarb on the side. You eat it by the stem, like a lollipop, and it tastes faintly of pancakes that have wandered into a meadow. The same dish reappears in Alto Adige as frittelle di sambuco, in Slovenia, in Hungary, in small dialect variations of batter and accompaniment, like a folk song carried across borders by people who had no idea they were singing the same tune.

The Danes and the Swedes prefer the cordial route — hyldeblomstsaft, fläderblomssaft — though they tend toward a thinner, more drinkable version than the British, designed to be mixed with sparkling water and drunk on the longest evenings of the year. In Hungary, bodzaszörp shows up at every village shop in early summer, sticky-bottled, alongside the sour cherry equivalent.

The plant itself is treated with a strange wariness across all these places. In Scandinavia and Germany there is the figure of the Elder Mother — Hyldemoer, Holda — a spirit said to live in the tree, from whom you are expected to ask permission before cutting. The traditional formula in Denmark, more or less, is to bow and say Hyldemoer, Hyldemoer, må jeg skære dine grene? before taking a branch. To ignore her is to invite trouble: bad luck, soured milk, restless sleep. Hans Christian Andersen wrote her a whole story.

Every part of the elder is faintly suspect, in fact, except in its proper season and form. The berries must be cooked. The leaves are mildly toxic. The wood is the wood from which, in one English folk tradition, the Cross was made, and in another, the wood from which Judas hanged himself. The flowers are the only part that everyone agrees is safe to eat raw, and even then only for the two or three weeks each year when they are open and pale and not yet beginning to turn.

It is, when you think about it, a remarkably narrow window of grace.

There is the inevitable confusion with Italian sambuca, the anise-flavoured liqueur, which is named after sambuco, the elder — though the link is genealogical rather than gastronomic, since modern sambuca is mostly star anise and the plant is at best a distant ancestor. A handful of small producers in Lazio still flavour their version with actual elderflower or elderberry, which is, as far as I can tell, the only way to drink sambuca without feeling that you've made a terrible decision in a bar at one in the morning.

And there is the medicinal lineage, too, which runs underneath all this. Elderflower tea was, and in some places still is, the first thing reached for when a cold begins to come on — a hot infusion of the dried flowers, sometimes with linden, sometimes with peppermint, drunk as much for the ritual as for the (apparently genuine) anti-inflammatory effect. My grandmother kept a tin of dried flowers next to the kettle, and used it interchangeably with aspirin, with a confidence that has not entirely been disproved.

What I think I love about elderflower, beyond the taste, is the fact that you cannot rush it and you cannot keep it. The season starts when it starts. It ends when the bushes turn green-brown and the flowers drop their pollen and begin, in their slow way, to become berries. There is no extending it, no greenhouse forcing it, no flying it in from another hemisphere. You either pay attention to a particular fortnight in late spring, or you don't, and if you don't, you wait a year.

Which is, perhaps, why every culture along the great hedgerow belt of Europe has found something to do with it. Anything this fleeting demands to be caught.

By the time I am writing this, my own bottles are already in the fridge: four of them, cloudy gold, with handwritten labels and the date. Enough cordial to see me through to next May, when I will go out into the lanes again, find the same shrubs in the same patches of hedge, smell that strange honeyed cat-air, and start the whole brief business over.