Marshmallow is similar to the garden Hollyhock - it has large pinky white flowers with five petals and large soft hairy leaves. It is one of four species of mallow found at Rye Harbour Nature Reserve and grows in marshy places, both fresh and salty. It is locally frequent along the estuaries of the Sussex coast, but in Rye Bay it had declined dramatically by the end of the 20th century, probably due to extensive grazing by sheep.
On the other side of the river Rother there was a group of the these plants that also held one of the very few colonies of the Red Data Book 1 (= very rare) Marsh Mallow Moth - confined to south-east Sussex/south-west Kent and a small area in north Kent.
So we developed a plan to increase the number of plants on the Sussex Wildlife Trust land at Castle Water and hopefully establish a new colony of the moth. Twenty years ago we had only a dozen plants scattered around Castle Farm on steep ditch banks where the sheep couldn't reach. So we collected seed from these plants and found they were easy to grow in pots and could be planted out in spring into wet grassland. Then we encouraged volunteers and some schools to help us and soon we had established a large population of plants that we hoped would one day attract the Marsh Mallow Moth. In 2014 after ten years of encouraging the plant we had our first sighting of the moth on the plants and they are still doing well.
These flowers are also a good as a source of pollen for bumblebees, so we continue to spread the seed to new areas of marsh on the reserve.
Our nature reserve manager Barry Yates recently told this story to Charlotte Smith on BBC Countryfile and they collected and then spread this year's seed at Castle Water - shown first on 25th October 2020.