I grow bonsai from the trees of an English hedgerow on a small balcony in south-west London, and write down what each tree did in each season so that I stop repeating my own mistakes.

Hedgerow Bonsai is a record of growing small trees from the species that make up an English hedge: hawthorn, field maple, blackthorn and hornbeam, with the odd dog rose and hazel that arrived by accident. I started in the spring of 2020, with more time at home than I knew what to do with and a narrow balcony in Twickenham that had held nothing but a folding chair. Six years on it holds about twenty trees in varying states of progress, and the folding chair has moved indoors.

None of the trees was bought as a finished bonsai. Most came from the hedge along the side of a friend's garden further out towards the county edge, which she was replacing section by section and was glad to see go somewhere useful. A few were grown from seed and a couple from cuttings. I never dig anything up from the wild or from land where I do not have the owner's say-so, and I would ask anyone reading to hold to the same rule.

I am not a trained horticulturist and I have killed trees. The entries record what I did, when, and what happened afterwards, including the blackthorn that sulked for two years and the hornbeam I left wired a month too long. Where something is generally accepted practice I say so, and where it is only what has worked on one windy balcony near the Thames I say that instead. Native trees are forgiving, but not infinitely so.