Bindweeds

Hedge Bindweed Common Morning-glory Hedge Bindweed Common Morning-glory

What are they?

The bindweeds form the bulk of the family Convolvulaceae. They are attractive plants with their showy, bell-shaped flowers, but several species have a reputation for being deep-rooted and very persistent weeds of gardens and agricultural land. The flowers consist of five petals, fused together to form a cone of thin, rather fragile petals. Most plants are climbers with twining stems, or trail across the ground, climbing when they find something to support them.

Where are they found?

Bindweeds are prolific growers and are most frequent on heavier, richer soils. The group is more or less easily divided into a handful of common and widespread species that are found in a wide range of habitats, plus a few species that are garden escapes and likely only to be found on rough ground or roadsides in urban areas.

Identification

A few species can be identified by their distinctive leaves, combined with their typical bindweed flowers. Others are less easy to tell apart and identification requires a look at the details of the flowers and their stems. The flowers have five sepals, but these are generally hidden beneath two, leaf-like bracts that surround the base of the flower. In the larger Calystegia species, the detail of these bracts separates the species, together with the presence or absence of hairs on the flower stalk. Note that all of the white species can also occur in pink, so flower colour alone should not be used for identification.



Field Bindweed      Convolvulus arvensis

Native. A widespread and common plant on arable land and in gardens and rough ground, but also in dunes, grassy roadsides and even shingle beaches. Flowers mostly June to August but sometimes also outside of this period. Smaller than the Calystegia bindweeds and more likely to be creeping on open ground rather than climbing. Ten different colour forms of the flowers have been described, based on the amount of pink or white and the presence or absence of purple spots at the centre (three are illustrated here).

Field Bindweed Field Bindweed Field Bindweed Field Bindweed
Habit
Flower
Leaf
Leaf
Field Bindweed Field Bindweed Field Bindweed
Form arvensis
Form decarrhabdotus
Form quinquevulnerus


Large Bindweed      Calystegia silvatica

Originally introduced as a garden plant but strong-growing and difficult to control. Now widespread and common throughout most of our region, most often as a vigorous species that twines over fences and hedges and climbs up into trees in urban and suburban settings. Flowers mostly late July to September. Best told from Hedge Bindweed by the flower bracts, which broadly overlap each other, leaving the sepals almost completely hidden beneath them. The flower stalk is hairless. The variety quinquepartita is rare and has the five petals joined only at the base.

Large Bindweed Large Bindweed Large Bindweed Large Bindweed
Flower
Flower bracts
Leaf
variety quinquepartita


Hedge Bindweed      Calystegia sepium

Native in all kinds of wetlands, especially fens and reedbeds. In roadside ditches it can occur alongside Large Bindweed. Flowers mostly late July to September. Best told from Large Bindweed by the flower bracts, which are smaller, leaving a gap that clearly reveals the sepals beneath them. The flower stalk is hairless.

Hedge Bindweed Hedge Bindweed Hedge Bindweed Hedge Bindweed
Habit
Flower
Flowers
Flower bracts
Hedge Bindweed Hedge Bindweed
Leaf
Seed capsule


Hairy Bindweed      Calystegia pulchra

Introduced as a garden ornamental. Rare, but long-lived and the handful of sites where it occurs have been known for many years. Flowers July to September. Flowers pink with two lines of hairs running down the flower stalks. The hairs can sometimes be difficult to find and an easier identification feature is in the leaves, which are less shiny than Hedge or Large Bindweed and which have a square-sided gap between the two basal lobes, rather than a V-shaped gap. Flowr bracts large and strongly overlapping.

Hairy Bindweed Hairy Bindweed Hairy Bindweed Hairy Bindweed
Flower
Flower bracts
Hairs on flower stem
Leaf


Howitt's Bindweed      Calystegia x howittiorum

A rare hybrid between Large and Hairy Bindweeds. Flowers July to September. Flowers pink with two, weak lines of hairs on the flower stalks. The leaves are typically intermediate between the parents, having the shiny look of Large Bindweed but with a relatively broad gap between the two basal lobes.

Howitt's Bindweed Hybrid Bindweed Hybrid Bindweed Hybrid Bindweed
Habit
Flower
Flower bracts
Leaf


Sea Bindweed      Calystegia soldanella

Native in coastal sand dunes. Flowers June to August. Trails along the ground, often through Marram-grass clumps. Flowers rich, deep pink. Leaves kidney-shaped and slightly fleshy or succulent.

Sea Bindweed Sea Bindweed Sea Bindweed Sea Bindweed
Habit
Flower
Leaf
Seed capsule


Tricolour Bindweed      Convolvulus tricolor

Introduced as a garden ornamental and occasionally found as a short-lived annual in urban areas on sown roadsides and borders. Flowers July to September. A low-growing, spreading plant rather than a climber. Leaves simple. Flowers richly coloure in blue, white and yellow.

Tricolour Bindweed Tricolour Bindweed Tricolour Bindweed
Flower
Flower
Leaf


Common Morning-glory      Ipomoea purpurea

Introduced from the Americas as a garden ornamental and occasionally appearing briefly where bird seed has been placed or spilt. Flowers July to August. A twining, annual, climber with flowers that open at night, remaining open into the day before closing by mid-morning. Closed flowers with rolled tops are thus more likely to be seen later in the day. Leaves broadly heart-shaped. Flowers deep bluish-purple, white or deep pink.

Common Morning-glory Common Morning-glory Common Morning-glory Common Morning-glory
Flower
Flower
Flower
Leaf


Ivy-leaved Morning-glory      Ipomoea hederacea

Introduced from the Americas and appearing from a variety of sources but never persisting. Flowers July to September. A twining, annual, climber with flowers that open at night, remaining open into the day before closing by mid-morning. Closed flowers with rolled tops are thus more likely to be seen later in the day. Leaves three-lobed, the upper leaves often simple. Flowers pale blue or becoming purple flushed as they wither.

Ivy-leaved Morning-glory Ivy-leaved Morning-glory Ivy-leaved Morning-glory
Flower
Flower
Leaf