The stems of sweet rocket in my garden have aged to purple, the seedpods on this large swathe of plants forming an interlocking mesh. Mothercare spiders have used their lattice to spin untidy nests, but it’s the truncated seed cases that catch my eye. For weeks I’ve seen them nibbled by the green caterpillars of orange‐tip butterflies; now there’s just one latecomer still feasting in my garden.

These seedpods are long and fine, the width of a darning needle, gently curving like a curlew’s beak. After emerging from orange eggs laid on flower stalks of sweet rocket, the butterfly larvae go through four moults, the final instar, or phase, being the caterpillars in my border. They then pupate, spending the winter in a rigid bow-shaped chrysalis that is easily overlooked as a thorn.

I leave the plants standing throughout winter, partly for the wildlife they harbour, partly because they look beautiful backlit by low sunlight. Sweet rocket is one of the common food plants of the orange-tip butterfly, others being hedge garlic, cuckoo flower and honesty – all plants that I grow. The butterfly’s specific name, the cardamine of reflects its link to these wildflowers.

My spring days, though dull of light, were uplifted by numerous orange-tip males as they patrolled the garden looking for the more subtly patterned females. Since then it’s gone quiet. My notebooks have just sporadic sightings of butterflies: the first peacock on 31 March, a red admiral at the end of May, t.