Best time to see: late Mar to mid May

Key facts

A plant of damp meadows, so called because its flowers open when the cuckoo starts to call

Food plant for the caterpillars of orange tip and green-veined white butterflies

Like the related garden weed, hairy bittercress, pods split suddenly, shooting the seeds a great distance

Extras

Plants up to about 60cm high; smooth, no hairs; flowers in a cluster on top of branched stems

Flowers are pale pink/lilac, about 2.5cm across, with four petals

Leaves often 20cm long, with paired rounded lobes, mostly low on stem; upper leaves smaller and narrower, hard to spot.