<em>Convolvulus</em>, Turkish convolvulus: sow, plant, care for

Description and botany

Convolvulus, more commonly called bindweed, is a plant native to rocky, arid and stony hills of the Mediterranean basin, particularly Turkey and Egypt. It belongs to the large family Convolvulaceae alongside ipomoeas and morning glories.

Although Convolvulus in Latin means “to wind”, not all bindweed species are twining! The genus includes around 250 species of herbaceous annuals, perennials and even undershrubs. Alongside wild species regarded as weeds, such as field bindweed (Convolvulus arvensis), mallow-leaved bindweed or Provence bindweed (Convolvulus althaeoides) and hedge bindweed (Calystegia sepium), which when happy can become invasive, creeping or climbing through neighbouring plants, there are non-invasive Convolvulus.

Among the most widespread species are Convolvulus cneorum, silver bindweed or Turkish bindweed, Convolvulus sabatius, Mauritanian bindweed and blue bindweed, which are perennial bindweeds, and Convolvulus tricolor, commonly called morning glory or tricolour bindweed, which is grown as an annual.

Under our climate, depending on species, they are grown as annuals or frost-tender perennials. Some bindweeds survive our mild winters and are able to withstand brief frosts down to around -10 to -15°C; the morning glory, probably the most tender, is grown as an annual in less mild regions.

Driven by rapid, vigorous growth, perennial or annual bindweed forms, unlike its ipomoea cousins, a dense, ramified bush with a compact, spreading or trailing habit, reaching 10 to 50 cm in height and up to 80 cm in spread. Convolvulus tricolor or morning glory forms a creeping clump, while Convolvulus sabatius is ideal for hanging baskets.

Convolvulus cneorum – botanical illustration by P.J. Redouté

Its endless flowering speckling the foliage begins in March–April (depending on region) and only ends with first frosts. In leaf axils and at branch tips appear small clusters of turbinate buds that open into funnel-shaped flowers 2 to 5 cm wide, solitary or grouped in threes or sixes in small cymes. Flowers are plicate into five segments fused at the base to form a bell set within a villous calyx. They are borne on a very short peduncle and show crenate margins with a silky underside.

These corollas, delicate and widely flared trumpet-shaped, open in solid or variegated shades. They appear as pretty trumpets: white, sometimes delicately washed with pale pink in Convolvulus cneorum, pastel blue in Convolvulus sabatius or indigo to sky-blue, soft pink to mauve, red or white in morning glory. The latter species stands out from its relatives by often unique markings with more varied colours arranged in concentric halos of three contrasting colours, hence its name Tricolor bindweed.

Silky texture of bindweed petals sometimes reveals fine veins through the corolla, recalling delicacy of petunia or ipomoea flowers. Throat containing yellow stamens is highlighted by a small star-shaped central eye that enhances corolla colour.

These fully opened corollas open in morning and curl up at dusk, renewing generously until autumn.

This long, melliferous flowering attracts many pollinating insects.

Flowers give way to dehiscent fruits in globose capsules containing very small seeds.

Vegetation is dense and vigorous, deciduous, evergreen to semi-evergreen depending on species and climate. Foliage varies by species. Well-ramified shoots bear small petiolate, entire, oblong-lanceolate leaves 3 to 6 cm long in Convolvulus cneorum or Turkish bindweed. The latter bears characteristic leaves covered with silvery, shiny bristles and remain evergreen year-round. Convolvulus althaeoides is characterised by leaves entire at base and increasingly deeply divided towards stem tips, similar to mallows.

Well adapted to Mediterranean climate of origin, bindweed shows hardiness variable according to species.

Some Convolvulus: C. sabatius, C. cneorum and C. tricolor

This dry rock-garden plant is easy to grow in full sun in a light, very well-drained soil, even stony, rocky or sandy, and tolerates limestone. In southern regions it will accept partial shade. In cold areas, it is best to grow it in a pot to protect from frost in winter and bring outdoors during the warm season.

Bindweed is ideal for hanging baskets, window boxes or containers, in a mineral or seaside garden, in rockeries, on edges of borders, over a low wall or in suspended baskets and urns from which it will trail in flowering cascades.

Main species and varieties

Most popular

Our favourites

Another interesting variety

Convolvulus cneorum - Silver bindweed

This very pretty shrubby bindweed species is dressed with superb evergreen silvery-green foliage, decorative all year round. This undemanding plant is an excellent choice for dry rock gardens, containers and coastal situations!

• Flowering time May to September
• Height at maturity 40 cm

See the product sheet

Convolvulus sabatius Moroccan Beauty

With its light trailing habit, it is the perfect variety for hanging baskets! It can withstand light frosts.

• Flowering time July to November
• Height at maturity 30 cm

See the product sheet

Blue Morning Glory - Convolvulus tricolor Royal Ensign seeds

A magnificent annual bindweed of striking blue. Floriferous, easy to sow, accessible to all. Ideal for hanging baskets.

• Flowering time July to October
• Height at maturity 16 cm

See the product sheet

Dwarf Morning Glory Royal Ensign Seeds

A mix of annual trumpet flowers in blue, sometimes pink or white. Its spreading, very bushy habit makes it suitable for edging flowerbeds as well as for pots or urns.

• Flowering time July to October
• Height at maturity 40 cm

See the product sheet

Convolvulus althaeoides

This running variety is notable for very divided foliage and vivid pink flowers. Plant in a dry rock garden.

• Flowering time May to October
• Height at maturity 40 cm

See the product sheet

Planting

Where to plant bindweed or Convolvulus?

Some bindweeds such as Convolvulus cneorum or silver bindweed and Convolvulus althaeoides are relatively hardy and withstand brief frosts (-8 to -15°C). Others, such as Convolvulus sabatius or Moroccan beauty, are grown as short-lived perennials in southern France, while morning-glory or Convolvulus tricolor is treated as an annual in our climate. Most will only survive in open ground in regions where frost is not too severe. In less favourable areas, bindweed can also be grown in pots or hanging baskets.

Undemanding, bindweed is happy in any well-drained soil and in a very sunny, sheltered position where it will flower more profusely. It tolerates drought well and prefers light, stony, calcareous or sandy soil, strictly without excess water. It will not tolerate stagnant moisture.

With rapid growth and low maintenance, bindweed is useful for bringing flowers to a seaside or holiday garden without watering.

Bindweed develops into a dense tapetum of flowers and forms a bushy groundcover, perfect in a dry rockery, in large containers, window boxes on a terrace or balcony, in hanging baskets, cascading over a low wall or in large flowering swathes to add splashes of colour to path edges, to flower a path and the edges of summer borders.

When and how to plant perennial bindweed?

Plant our Convolvulus perennials as plug plants or bucket-grown plants in open ground or in pots, only once risk of severe frost and extreme heat has passed, from March to May or from September to November. Meanwhile, you can pre-cultivate them in pots to hasten their growth in a conservatory or a bright greenhouse at a temperature above 14°C before planting outside.

In open ground

Plant about 3 to 5 bindweed plants per m². Space plants 30 to 60 cm apart in all directions depending on variety. On path or bed edges, plant in quantity for a beautiful, low-maintenance display. In heavy soils, add river sand and potting compost.

In ground that retains too much moisture, don’t hesitate to set your Convolvulus in a raised bed or on a mound where water will run off easily.

• Prepare ground with a shallow digging
• Dig a hole 2 to 3 times larger than size of rootball
• Spread gravel or clay balls for perfect drainage
• Mix extracted soil with stones and gravel
• Place plug plant in centre of hole, collar level with soil
• Bring soil back to fill hole
• Firm down
• Water abundantly

How to plant Convolvulus in pots or hanging baskets

All Convolvulus are perfect in hanging baskets, window boxes, urns or large pots from which they tumble in pretty cascades! In less favourable regions, this is an excellent option. Plant in a rich, well-draining mix composed half of potting compost and half of river sand.

• Soak rootballs well before planting
• Lay a good drainage layer (gravel or clay balls) in pot or window box
• Plant in a mixture of garden soil, potting compost and coarse sand
• Place in full sun
• Water well then regularly once surface soil has dried

You will find on our blog all secrets to plant a window box.

Scene with a Convolvulus cneorum showing superb silver foliage in foreground

Sowing

If you already have annual Convolvulus plants, you may have collected the small seeds contained in the dried capsules after flowering for future sowing. If not, choose from our morning glory seeds and sow in seed trays or seed pans from March to April, or outdoors in May or June when soil is well warmed and temperatures reach 18–20°C.

In a seed tray

• Soak morning glory seeds in water for about 2 hours
• Sow seeds 3 cm deep in a tray filled with potting compost and a little sand
• Keep moist at 20°C until germination, which occurs in 5 to 14 days
• Prick out seedlings individually when they have become sturdier, or, if outdoor temperatures permit, plant them outdoors or into larger pots without disturbing the root balls

For direct sowing in the ground, from May to June:

You can also sow morning glory seeds directly in warm soil.

• Loosen soil to a spade’s depth
• Sow in clusters of 4 to 5 seeds in holes the depth of the seeds, every 30 cm
• Cover with a few centimetres of potting compost
• Firm down lightly with the back of a rake
• Keep soil moist until germination, which takes 1 to 2 weeks
• Thin seedlings to leave one young plant every 15 to 20 cm

To find out all about sowing annual seeds, discover our advice sheet: “Sowing annual seeds: how to get it right, directly in the ground or in trays”

Caring for Convolvulus

Once young plant is well established, Convolvulus requires little maintenance. It is invaluable in seaside gardens or without watering because it resists drought very well: water during dry periods, once or twice a week, allowing soil to dry out thoroughly between waterings. In winter, water them only sparingly. Avoid excess water and always let soil dry out between waterings.

Remove faded flowers as they appear with a shear to prolong flowering.

For perennial varieties and in mild climates, prune clumps lightly at end of flowering and protect them with a good mulch of dead leaves. In cold regions, perennial Convolvulus can be brought into a frost-free space.

In less mild regions, Convolvulus grown in pots must be repotted each year. In cold regions, lift morning glories that perish at the first frost.

Pests and diseases

Only red spider mites in very hot, dry weather can be a formidable enemy of convolvulus: spray foliage to dislodge them as they hate moisture.

Propagation

shrubby or perennial convolvuli are propagated by cuttings from May to July or divided in spring, while the Morning Glory, Convolvulus tricolor or tricolour morning glory self-seeds each year; follow our advice above to sow the Morning Glory seeds.

Division

In March, divide clumps of perennial Convolvulus aged 2 or 3 years.

• Lift clump with fork or spade
• Separate root ball into several divisions each with roots
• Replant immediately each young plant in pot or garden in well-draining soil

How to make a cutting of Convolvulus

• Take non-flowering stem tips about 15 cm long
• Remove lower leaves, keep only 2 upper leaves
• Plant cuttings in very light mix of potting compost and sand kept slightly moist until they have rooted
• Place cuttings at 20 °C
• Grow in individual bucket sheltered from frost until next spring
• Plant out in open ground after last frosts or into larger pots

Companion planting for Convolvulus

In hanging baskets, window boxes, rock gardens, at edges of beds or borders, the Convolvulus adapts to every need, planted in ground or in pots, in all natural or naturalistic or romantic dry gardens and seaside gardens to contribute to very floriferous scenes. With pastel or vivid colours, it allows chic or dynamic combinations.

At edge of a romantic bed harmonised in pink, blue and white, silver bindweed and Convolvulus sabatius will bring a delicate touch at the feet of roses, lavateras, Alcea Rosea or a Cape shrubby mallow, surrounded by yarrow, agastache, Italian bugloss, Gypsophila, Echinops, sea hollies.

An idea for a combination on a sunny slope: Convolvulus cneorum, Genista tinctoria ‘Royal Gold’, Stipa tenuifolia and Erigeron karvinskianus

To compose a tapetum grey and downy, plant silver bindweed near a Cerastium tomentosum (Mouse-ear), Anaphalis margaritacea or silver immortelle, artemisias, and Armeria maritima (sea-pinks).

In rock gardens, pair Convolvulus cneorum with plants that enjoy similarly slightly dry conditions such as alpine asters, campanulas, Dianthus deltoides or Dianthus arenarius (Sand Pink), helianthemums, Arabis caucasica, Delosperma, bergenias and aubrietas. Punctuate with a few clumps of Carex, blue oat grass, Dianthus plumarius, blue fescue.

In a mineral-style garden, offer silver bindweed Mediterranean perennials such as santolinas, immortelles, rosemary and creeping ceanothus, lavenders, cistus and sedums.

Its flowers in pastel shades will work wonders with purplish foliage of heucheras or glaucous leaves of poppies to create scenes of great softness in heart of summer.

In a bed of summer-flowering perennials, Convolvulus will slip easily between penstemons, light grasses, perennial flax, nigellas.

In pots and hanging baskets, Mauritanian bindweed and Morning Glory will form very attractive combinations with verbenas, Petunia surfinia, Bidens, Lantanas, zinnias, Diascias in scenes of contrasting or softer colours.

An example of a combination in a hanging basket: Convolvulus sabatius, Lobelia ‘Snow White’ (or ‘Hot Bavaria’, that will look lovely too!), Petunia ‘Tumbelina Belinda’ and Dichondra ‘Silver Falls’

In pots, mix them with other annual plants such as impatiens, ipomoeas, lobelias and geraniums.