Stand by a riverbank or damp meadow in August and you may catch it before you see it — a warm, sweet, faintly almond scent drifting on the air that is like nothing else in the British countryside. Look for the tall, frothy, cream-white flower heads nodding above the vegetation, and you’ve found meadowsweet: one of the most beautiful, most fragrant and most historically significant wildflowers in these islands.

There is a moment in late May — blink and you’ll miss it — when the hedgerows along Hertfordshire’s country lanes seem to exhale. Great flat-topped clouds of creamy white blossom appear almost overnight, filling the warm air with a scent that is floral, honeyed, and unmistakably, gloriously English. That’s elder. And if you’re not already on first-name terms with it, now is the time to be introduced.