NEXT month in June, travel into the Dales to visit one of our stunning wildflower hay meadows. To see them at their best, wait for a warm and sunny day.

These meadows seem a world away from most modern meadows and pasture where grasses dominate, to the exclusion of everything else. The wildflowers and insects have vanished.

What is it that makes these upland hay meadows so special?

- No chemical fertilizers or animal manure are added.

- They are cut just once a year for hay, in late July or early August. This allows plants to flower, set seed and the seed to be dispersed. The modern way of cutting twice a year for silage just doesn’t give our native wildflowers a chance to complete their life cycle.

- In autumn after the hay has been harvested, these meadows are then grazed by cattle. Cattle are far better than sheep for meadow biodiversity. Sheep are, after all are nature’s ‘lawn mowers’ taking the sward down to just 2cm above soil-level. Cattle have the additional benefit of disturbing the soil, pushing seeds into the ground, and hoofprints leaving areas of bare soil for new plants to become established.

- The final ‘magic ingredient’ is the presence of hemi-parasitic plants. The most important of which is Yellow Rattle. Although these plants can survive independently, they thrive by obtaining nutrients from the roots of neighbouring plants, in particular grasses. The vigour of the parasitised plant is reduced which allows more delicate plant species to flourish and vegetation diversity to increase.

Yellow rattle (Rhinanthus minor) was once seen as an indicator of poor grassland by farmers. Now in more enlightened times, farmers are being encouraged to increase grassland biodiversity. Both the Yorkshire Dales national park and Nidderdale AONB are using fresh Yellow Rattle seed and ‘green hay’ from doner sites, to restore hay meadows.

Yellow rattle is easily recognised, with its distinctive two-lipped yellow flowers. Behind the flower, joined sepals form a green bladder (the calyx). This gives the appearance of a cuckoo emerging from a clock or a yellow canary from its egg, mouth agape. The calyx turns brown in fruit, and holds the capsule in which the seeds rattle, giving the plant its common name.

Once Yellow Rattle has been successfully introduced it can reduce the competitive vigour of grasses by as much 50%, thereby, allowing other wildflowers to become established. Three cheers for the floral canary without which none of this would be possible.