Convolvulus

Convolvulus flowers

Large family of flowering annuals, perennials and shrubs with a diverse range of growing habits, including: erect, scrambling, climbing and trailing forms.

Family: Convolvulaceae
Botanical Name: Convolvulus
Common Names: Bindweed, morning glory

Foliage: Semi-evergreen or deciduous, simple heart-shaped or palmately divided leaves. Green or silver-grey in colour.

Flowers: Open funnel or saucer-shaped flowers.

Flowering Period: Summer to early autumn.

Soil: Well-drained soil (chalk, sand or loam). Acid, alkaline or neutral pH.

Conditions: Full sun. Best planted in a west or south facing aspect, in a sheltered location.

Habit: Can be bushy, erect, scrambling, climbing or trailing, depending on species.

Type: Annuals, perennials or shrubs.

Origin: Worldwide

Hardiness: Hardy to half-hardy, depending on variety.

Planting and Growing Convolvulus

Thrives in any ordinary well-drained soil, even poor soils, so long as the site is sunny and sheltered. Drought tolerant once established.

Shrubby perennials do well in the rock garden or containers. Low growing varieties are suitable for the rock garden or scrambling down a bank. Larger varieties make ideal climbers for walls, fences or a trellis.

Taking Care of Convolvulus

Protect from cold until established and keep weed free. Deadhead regularly to prolong the flowering period.

Protect perennials and shrubs from cold winds and winter wet.

Pruning Convolvulus

Annual climbers do not need pruning.

Shrubby forms like C. cneorum can be pruned by about a third in the summer (after flowering) to keep then compact and bushy.

Pests and Diseases

Generally pest and disease free.

Propagating Convolvulus

Sow the seed under glass in trays of good seed compost, in early spring. Keep at an even temperature of 15-18°C (59-64°F). Prick out, pot on and harden off before planting out in late spring. Alternatively, sow direct where they are to flower, in well prepared ground, in mid spring. Gradually thin to 9in (23cm) apart.

Increase shrubs and perennials from softwood or semi-hardwood cuttings in summer. Root in well-drained compost under a gentle heat.

Popular Varieties of Convolvulus

Although related to the pernicious field bindweed C. arvensis, most ornamental garden species are not as rampant or invasive, although they are less hardy.

Convolvulus althaeoides (mallow bindweed) is a prostrate scrambling/trailing perennial with silvery green leaves and pale pink flowers.

Convolvulus sabatius (blue rock bindweed) is a woody-stemmed trailing perennial with attractive light blue flowers (July-October) set against blue-green foliage. Ideal for the rock garden. Not fully hardy. Height to 18in (45cm).

Convolvulus cneorum (silverbush or shrubby bindweed) is a half-hardy small evergreen shrub, with silver lanceolate leaves and white flowers that are sometimes ribbed on the reverse side with pink. Originating from the Mediterranean it is not fully hardy in UK, so provide the protection of a south-facing wall. A choice small plant that is ideal for container growing. Height and spread 2ft (60cm) or more. For sale at Crocus.

Convolvulus tricolor (syn. Ipomoea tricolor) is a climbing or scrambling annual or short-lived perennial, with dark-green foliage and blue flowers, often with a white and/or yellow throat. Flowers from July to September. Supported height 6-12ft (2-4m). Popular varieties include:

  • 'Blue Flash' a bushy plant with deep blue flowers with a yellow and white centre.
  • 'Blue Ensign' (RHS Award of Garden Merit) a dwarf variety with brilliant blue flowers with white then yellow centres. Seeds available at Thompson & Morgan.
  • 'Dwarf Rainbow Flash' large flowers in mixed colours (pink, carmine, rose, blue, purple and lilac). Height to 6in (15cm).
  • 'Heavenly Blue' a twining annual with heart-shaped leaves and funnel-shaped deep sky-blue flowers.