Abstract erotica, Japanese giants face off and spring arrives in Oxford – the week in art

Alexis Ralaivao’s provocative paintings, Hiroshige and Hokusai in perspective and a grand survey of flowers in fine art – all in your weekly dispatch

In Bloom: How Plants Changed Our World
Lovely flower paintings to herald the spring, but all is not what it seems in this survey of how science, trade and tulip crazes helped shape the modern world.
• Ashmolean Museum, Oxford, from 19 March to 16 August