William Howard with his Barbican garden

William Howard: ‘This garden is about memories.’ Photograph: Sophia Evans for the Guardian

I love concrete. I worked with it most of my life – I was a civil engineer, and worked on projects from an Augustinian church to Stansted airport. Concrete is brutal. It needs softening.

I will be 80 this year, and here in my flat in the heart of the City, only half a mile from where I was born, I have tried to lead by example, planting up my narrow balcony to create the hanging gardens of Barbican. In summer we open all the doors so it becomes part of the flat. There are always people coming round: I am chair of the Barbican Horticultural Society and all my grandchildren love coming here, too. We breakfast among the plants and watch the wild visitors. The flat faces west, so it gets the afternoon and evening sun, but sometimes, when a window opens opposite, we’re hit with reflected morning light. It reminds me of a scene in Jacques Tati’s film Mon Oncle, when Monsieur Hulot discovers that, by wedging a window open at a certain point, he can direct the sunshine on to a nesting bird, prompting it to sing as if it were dawn. His face lights up with pleasure.

A wren nests on the balcony most years. Sometimes you can’t see where exactly because of all the ivy, but the fledglings will zing past while we’re eating; they’ll even join us at the table. It is so peaceful up here, much quieter than where I used to live in the countryside.

Some years, the clouded yellow butterfly joins us from abroad. I’ve loved butterflies since seeing them, at the age of 10, in an ancient Egyptian tomb painting of Nebamun at the British Museum. In the painting, I saw the tiger butterflies showing the wing detail. I have been round the world since, looking at butterflies, plants and birds, including China five times – I love China.

I have been so lucky to spend much of my life outdoors. This garden is about memories, sharing and reminding people to look – really look. Like Jacques Tati.

My favourite spot

Sitting in my armchair, listening to the fountains below and looking diagonally across the balcony at the tower of St Giles, Cripplegate, where the poet John Milton is buried. The view of the cupola is framed with climbers, a lovely, pink-flowered mandevilla and a cup-and-saucer vine, Cobaea scandens.

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