Petal passion, super-surreal Polaroids and Billy Childish’s California – the week in art

Expertly curated flower paintings, the garage-rock star’s hazy expressionism and a masterpiece from a Morrisons receipt – all in your weekly dispatch Handpicked: Painting Flowers from 1900 to Today Jim and Helen Ede, founders of Kettle’s Yard, cared almost as much about the fresh cut flowers in their gallery as the art. This show looks at artists who share that floral passion, from Henri Rousseau to Lubaina Himid. Kettle’s Yard, Cambridge, 25 April to 6 September Billy Childish: This Is The Universe… Big Isn’t It?Garage-rock superstar does his hazy, expressionistic thing with new paintings of the California desert. Carl Freedman Gallery, Margate, 26 April to 14 June Katharina Grosse: I Set Out, I Walked FastThe master of giant, building-sized paintings returns, with yet more enormous site-specific interventions, and some smaller works too. White Cube Bermondsey, London, 22 April to 31 May Les Krims: FictcryptokrimsographsUltra-weird, super-surreal staged Polaroids from the mid-1970s that undermine any idea of photographic truth. Graces Mews, London, until 23 May Racheal Crowther: Liquid TrustScent-based installation art about bodies and the military-industrial complex i