We all love a very long-flowering tulip, so last spring we recorded exactly how long each one looked good. Some ­tulips age with elegance, but not all. You’ll find varieties with lots of green in the petals – ‘Viridifloras’, and varieties such as ‘Evergreen’ – flower the longest. If you look at the petals, the green section is more like a calyx, and has a stronger, more robust texture than petals. Dark reds also seem to last better than most in the garden; also the ­peony-flowered varieties, where the nectaries have been bred to be extra petals, so they’re sterile (although not good news for pollinators). These flower for a good month and last at least two weeks in the vase.