6 Aug 2013
Swallowtail butterflies and a fennel bush
A few years ago, I bought a bronze fennel bush at a garden centre specialising in herbs, near Chesterfield in Derbyshire. We kept it in a pot on our roof terrace in London, where it quietly survived. We then then took it to Normandy when we moved here, put in in a proper garden, and it has thrived: this year it reached nearly two metres.
It is not the bulb fennel, sometimes called Florentine fennel, sold in supermarkets and elsewhere for use in salads and with fish. This one starts with intensely bushy stalks, thickly covered with fronds; bit like dill on steroids. Gradually the stalks get longer and the fronds more separated. Eventually, it produces a host of yellow flower heads, flat with a mass of tiny flowers, like all the umbelliferae plants. These flowers are covered with bees, hoverflies and other insects. Finally the flowers turn to seeds. I gather these and keep them for cooking. Their liquorice taste adds a deep flavour to stocks, soups and sauces, to some salads, and as a component of any spicy dish. I probably use them at least five times a week. In winter, the plant just dies back to the ground.
Each year, for a day or two, in late may or June, we have a swallowtail butterfly or two flying in the garden, and always ending up on the fennel. Then we have caterpillars, starting as small, dull things a centimetre or two long, but within days becoming three times the size, and turning black and green. They sit on a stalk and eat the fronds until all that is left is the stalk, and they move to another. They don't damage the plant; unlike some pest species, there are usually only up to a dozen. Three weeks later they have all gone, each turned into a chrysalis out of sight.