Sea Bindweed, Calystegia soldanella
On holiday in Cumbria last week, we visited the magnificent sand dunes at Sandscale Haws. We didn’t see any of the Sea-kale, Crambe maritima, I wrote about in April but there were lots of other lovely plants, including masses of Burnet Rose, Rosa spinosissima, at the back of the dunes, Sea Rocket, Cakile maritima, on the beach and dune slacks full of orchids.
One of the highlights of our visit was a big patch of Sea Bindweed, Calystegia soldanella. It was growing on a south facing slope a little way in from the edge of the dunes.
Sea Bindweed, Calystegia soldanella, in the dunes at Sandscale Haws in Cumbria (17th June 2026).
Where the Sea Bindweed grows
Sea Bindweed, Calystegia soldanella, is one of the delights of Britain’s coasts and one of my favourite plants. It has beautiful striped flowers, pink decorated with five narrower white bands. Its leaves are elegant, shiny and kidney-shaped and its stems sprawl over the ground.
Sea Bindweed often grows in scenic places too. As I write (with curtains closed to keep the sun out) we are experiencing record-breaking June temperatures (38 degrees Celsius at the moment) but just looking at a photograph Sea Bindweed on a beach in the Isles of Scilly is making me feel much better.
Sea Bindweed, Calystegia soldanella, on a beach on St. Agnes, Isles of Scilly (June 2010).
Sea Bindweed is a member of the Convolvulaceae (Bindweed family). The family includes the edible Sweet Potato, Ipomoea batatas, and the parasitic Dodder, Cuscuta epithymum, that I wrote about in July 2021.
Bindweeds, especially other species of Calystegia such as Hedge Bindweed (Calystegia sepium) and Large Bindweed (Calysegia silvatica), grow very rampantly and are hated by many gardeners because of their persistent roots and invasive growth habits (note 1). Field Bindweed, Convolvulus arvensis, is another close relative and can also be persistent weed . All three species have very attractive flowers and those of Field Bindweed are delightfully perfumed and well worth a sniff! (note 2). [See “Relatives of Sea Bindweed” below for pictures of Field and Large Bindweed.]
Sea Bindweed, Calystegia soldanella, is their more refined coastal cousin. It too has long roots and these can grow more than 70 cm under sand cover (note 3) but it prefers growing on sand dunes and above the strand-line on sand and shingle beaches, so is unlikely to be encountered as a “weed”. It is a trailing perennial herb, rather than a vigorous climber, and it gently grows across sand or amongst other vegetation. Its flowers are beautiful, and typical of our other species of Calystegia) tin having no noticeable scent.
Sea Bindweed is restricted to coastal sites in the British isles, though it is hardy to -10 to -15 degrees Celsius (hardiness rating H5). It needs to be tough to cope with salt, hot sunshine and drought conditions.
On Sea Bindweed’s current status, the 2020 BSBI Plant Atlas says: “The loss of sand dunes and increased recreational disturbance on those that remain have resulted in many losses of this species during the 20th century, particularly in southern and eastern England, although it seems to be relatively resistant to trampling. Its distribution since the 1990s appears to be stable, save for coastal areas in eastern Scotland, where there are very few recent records.”
Distribution map of Calystegia soldanella from BSBI Online Plant Atlas 2020.
Calystegia soldanella is a native of the British Isles. It is scarce in Northern Scotland, although it can be found on Orkney. It is included in rare plant registers for several Vice-Counties.
It is a native coastal plant in many other temperate and sub-tropical parts of the world. The Plants of the World Online website gives the native range for Sea Bindweed as follows: Europe (but not Scandinavia), North Africa, the Middle East and Iran, the United States (western states but also Virginia), parts of South America, South Africa, Australia and New Zealand.
The New Zealand Plant Conservation Network gives an account of the plant in New Zealand.
The BSBI website says it is “widely naturalized outside its native range” but Plants of the World Online doesn’t mention this.
The Royal Horticultural Society (RHS) website suggests growing Calystegia soldanella in a gravel or coastal garden, in sunny conditions with very sharp drainage. It is “unlikely to become a garden weed“. It suggests that slugs and snails may be attracted to the plant. The EarthOne website has more growing tips. I don’t intend to try but I wonder whether Sea Bindweed would grow in the sandy soil on my allotment?
Sea Bindweed in pictures
Time for some more pictures.
The first one shows a flower bud just above two open flowers:
Sea Bindweed, Calystegia soldanella. Flower bud at top of photograph, above the flowers.
Plants flower from June to September, with a peak in June to July. After flowering, Sea Bindweed forms its seeds.
The seeds are comparatively heavy and tend to remain on the sand surface, where they can remain until winter storms wash them out to sea. When they looked at soil core samples the authors of a study in Tuscany (Italy), failed to find any seeds and concluded that the local spread of Sea Bindweed was by its extensive root system, leading to large clonal patches of plants (note 3).
For long distance dispersal, Sea Bindweed seeds are able to float for a long time with maintaining viability and up to 90% of the seeds can germinate after nine months of immersion in sea water. This may help to explain the plant’s global distribution.
Populations of Calystegia soldanella in Europe show a low level of genetic divergence, as do Korean populations. This lends support to the hypothesis that seeds can be spread for long distances by sea (note 4).
Sea Bindweed, Calystegia soldanella. Leaves and a seed pod. Holkham Dunes, Norfolk (July 2022).
Even when not in flower, Sea Bindweed’s shiny, kidney-shaped leaves are very distinctive.
Sea Bindweed and wildlife
Sea Bindweed flowers are insect pollinated.
The Native Wildflowers website says they are “mainly pollinated by hawkmoths.” I’ve never observed this but I don’t hang around in sand dunes at night.
The Plants for a Future website mentions pollination by bees and moths and butterflies.
I have a couple of photographs of bees visiting the flowers: a species of furrow bee (Lasioglossum or Halictus sp.) on a beach on St. Agnes in the Isles of Scilly in 2010 and, from last week, a species of bumblebee (Bombus sp.) at Sandscale Haws.
Sea Bindweed, Calystegia soldanella, with visiting furrow bee (Lasioglossum or Halictus sp.). St. Agnes, Isles of Scilly (June 2010).
Sea Bindweed, Calystegia soldanella, with visiting bumblebee at Sandscale Haws (June 2026).
Plant Associations
The BSBI Plant Atlas notes that Sea Bindweed often grows with Sea Holly, Eryngium maritimum – as in this photograph from Sandscale Haws:
Sea Bindweed, Calystegia soldanella, with Sea Holly, Eryngium maritimum. Sandscale Haws, Cumbria (June 2026).
On a visit to Winterton Dunes, Norfolk Flora Group found Sea Bindweed scrambling amongst the abundant Marram Grass Ammophila arenaria.
At Sandscale Haws, Sea Bindweed was also growing with Common Restharrow, Ononis repens. Both plants had pink flowers but the flower shapes and shades of pink made a pleasing contrast.
Sea Bindweed, Calystegia soldanella, with Common Restharrow, Ononis repens. In the dunes at Sandscale Haws in Cumbria (June 2026).
Other names for Calystegia soldanella
Other English names for Calystegia soldanella include: Scotch Scurvy Grass, Sea Bells, Seashore False Bindweed, Shore Bindweed, Shore Convolvulus and Beach Morning Glory.
A more romantic name is “The Prince’s Flower”. On 23 July 1745, Bonnie Prince Charlie (Charles Edward Stuart) landed on the island of Eriskay in the Outer Hebrides, with seven companions (known as the the Seven Men of Moidart). The beach where he landed is now known as Coilleag a’ Phrionnsa (“The Prince’s Strand).
The story goes that seeds of Sea Bindweed fell out of his pocket when he took out his handkerchief and the plant took root.
Whether or not this is true, Sea Bindweed still grows on that beach today.
Sea Bindweed as food
Sea Bindweed has been used for food.
In New Zealand “Maori gathered the thick, white, fleshy roots and pounded these to form a pulp, this was then used as a relish to flavour some meats.”
The Plants for a Future website says that young shoots can be cooked as a vegetable or pickled and used as a samphire substitute. However, it advises caution because the plant “might have a purgative effect”.
The Plants for a Future website also lists some possible medical uses for the plant.
I think I’ll stick to admiring its flowers.
Further Reading
See the Botany In Scotland blog for an interesting description of Calystegia soldanella and this and the Wild Flower Finder website for more photographs.
Mike Crewe’s Flora of East Anglia website has a useful page comparing different bindweeds.
Relatives of Sea Bindweed
Large Bindweed, Calystegia silvatica, has short, wide bracteoles which overlap where they meet, hiding the sepals. On our allotment site (June 2025). The sepals are visible in its close relative, Hedge Bindweed, Calystegia sepium.
Field Bindweed, Convolvulus arvensis. On a road verge in Suffolk (June 2025). Although this plant was low and spreading, the flowers and leaves were very different to those of Sea Bindweed. (The leaf just left of centre belongs to a Common Mallow plant.)
Notes
Note 1 – When they are in flower you can tell apart Hedge Bindweed (Calystegia sepium) and Large Bindweed (Calysegia silvatica) by looking at their bracteoles, the green leaf-like stuctures at the base of the flower. Large Bindweed has short, wider bracteoles which overlap where they meet. Hedge Bindweed has narrower, longer bracteoles with a gap between them, allowing a glimpse of the sepals.
Note 2 – We have lots of Field Bindweed, Convolvulus arvensis, on our allotment. I tolerate it at the edges of the plot but remove shoots that emerge in vegetable beds. Most of the roots are unharmed when I do this but I prevent the plant from outcompeting or enveloping other plants.
When we took on our allotments over 25 years ago we double dug each plot to remove roots of perennial weeds and found Field Bindweed roots in the subsoil more than two spade depths down. Since then, our aim has been to control the plant rather than eliminate it.
I didn’t realise Field Bindweed had scented flowers until about ten years ago when Vanna invited me to sniff some when we were at Warham Camp in North Norfolk. I had sniffed Large Bindweed flowers as a child and had assumed that Field Bindweed had no scent either, but I was wrong.
Note 4 – R. Arafeh,”Molecular phylogeography of the European coastal plants Crithmum maritimum L., Halimione portulacoides (L.) Aellen, Salsola kali L. and Calystegia soldanella (L.) R. Br.” The paper has information about seed viability after immersion in sea water and its long roots are shown in figure 2.