If your fennel has bolted, there is no need to pull it up. You can let it flower and then collect the seed to use in cooking. Like the rest of the plant, the seeds have an aniseed flavour, and they are very useful in the kitchen – the seeds from Bronze Fennel are slightly milder than those of Bulb Fennel, but both are edible and worth saving. Even if you don’t particularly like the flavour, you may find that collecting the seed and popping them into a small jar makes a nice homemade gift for a friend or neighbour.
Wait until the flowers start to turn brown and dry out. Using a pair of secateurs, you can cut off the whole seed head, leaving a little of the stalk attached to make it easier to handle them. It’s best to do this on a dry day so that the seed heads are dry when you pick them. Put them into a paper bag and leave it in a cool, dry place to allow them to dry out fully. 7-14 days should be enough for them to dry completely – check the seeds by trying to squeeze them between your thumb and fingernail. They should be almost tough enough to withstand any indent. Once you’re happy they are dry enough, give the paper bag a little shake to set the seeds free, and then you can store them in a jar.