Boston is full of mourning and magnolia. Boylston Street, where limbs and lives were shredded on Monday, is still a crime scene. But parallel to it is Commonwealth Avenue, one of the world’s most handsome boulevards, lined with dark-red sandstone houses, where a great river of blossom now flows – flesh-pink cups, for the most part, but here and there a sprinkling of feathery white.

Bostonians, of which I was one for many years, come to gawk at the sudden shamelessness of the flowering, so at odds with the city’s customary inwardness and severity. Spring here is meant to be a gift as lavish as the winter is brutal. Until now, the usual threat to this outburst of April happiness has been the odd freak storm landing globs of clotted snow on the daffodils, breaking the necks of their stalks and the hearts of us gardeners.

But the spring reawakening is also an act of history. Patriots’ Day, celebrated only in Massachusetts, and the day the murderers chose for their atrocious gratification, commemorates the beginning of American liberty, when on April 19 1775 on Lexington Green British redcoats in search of secret arms caches ran into a citizens’ militia determined to stop them. In a chaotic exchange of fire, eight of the Lexington Minutemen were killed. There was blood shed on that morning, too, but unlike whatever demented motives might have led to the Boylston bombings, Lexington’s blood was spilled in reluctant desperation and as an act of resistance to coercion.