There are two types : field bindweed and hedge bindweed.
Although not invasive in the sense that they have been introduced from abroad, they can however become a problem as they invade gardens - hence that word, weed. But they are attractive and many a gardener must have been tempted to get one, have it grow rampant, and then dispose of where it could possibly beceme an escapee. It can be argued that bindweed is not an invasive species as it is from western Europe, but it can still be problematic where it colonises areas beyond our control.
The MDPI / Agronomy website approaches these plants from a control point of view, but is also more detailed in differentiating between them. See the link below.
Although field binweed has not been see wild in West Dunbartonshire, you have very likely seen it in surrounding areas or in gardens. It will be more familiar to you as morning glory, either white or a glorious blue.
FIELD BINDWEED : Convolvulus arvensis
Wildlife Trusts describes the field bindweed as a trailing or creeping plant, occasionally climbing up to 2m. Its funnel-shaped flowers may be pink, white, or pink-and-white striped, and are sweet-scented, unlike the larger kinds of bindweed. Its leaves are grey-green and arrow-shaped.
From this point on it gets confusing. Both of these have white, pink or pink-&-white flowers. It is easiest to simply look at where it is growing. Field bindweed obviously, usually, grows in fields.
HEDGE BINDWEED : Calystegia sepium
As its related plant, the field bind weed, this is a climbing plant where it can be found in woodlands, hedges, riverbanks and gardens. It has become a pest in some places. It has large, trumpet-shaped, white flowers and arrow-shaped leaves. Pink variants are less common.
A glorious bloom of hedge bind weed in June along the Leven towpath where it is met by Alexander Street. But don't be fooled by the leaves. Those in this picture are from a bramble. The two plants have simply intertwined.
A few days later and no flowers are evident at all. Probably all picked. But it has certainly not gone away. There it is climbing the stone wall of Lomond Distillery. near India Street and the Leven towpath.
And a closer view of the leaves.
Furthet up the Leven several bindweed plants are happiily creeping over the riverbank and finding support on the stonework and other plants.
Delicate and silky flowers.
Opportunistic, groping, entwining, binding stalks. This is the wall of the park at Halkett Crescent as overlooked by Heather Avenue in Alexandria.
HAIRY BINDWEED : Calystegia pulchra
The RHS use the name Dahurian bindweed and note that it is potentially harmful. As with the other bindweeds, this has been introduced and has become naturalised with the possible threat of overwhelming native plants.
Otherwise this is very similar to the pink field bindweed. A differentiating feature is the way the pink petals have white stripes within the folds and thin black stripes can also be seen. It has hairs and narrow wings along its flower stalks.
Hairy bindweed growing along the upper Leven towpath.
This one was seen in early September on the Leven towpath.
Also see : INVASIVE SPEOIES OF PLANTS : index.asp?pageid=732296
MAKAQUES : http://www.makaques.com/gallery.php?sp=1676
MDPI / Agronomy : https://www.mdpi.com/2073-4395/10/8/1184#:~:text=Field%20and%20hedge%20bindweed%20are%20closely%20related%20species,rhizome%20development%20and%20above-ground%20runners%20%5B%2013%20%5D.