Clematis patens

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open-flowered clematis

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Synonyms

Clematis caerulea

Climber Wall Shrub

Slender, deciduous climber long cultivated in Japan, an old species clematis about 3m tall, with single upright flowers to 13cm across, in variable colours from white to shades of pink and blue with reddish-mauve anthers, flowering from mid spring to early summer, then late summer

Position

Full sun, Partial shade

Soil Types

Chalk, Clay, Loam, Sand

Max Height

2.5-4 metres

Max Spread

1.5-2.5 metres

Size

Time to Maturity
2–5 years
Max Spread
1.5-2.5 metres
Max Height
2.5-4 metres

Growing Conditions

Chalk Clay Loam Sand
Moisture
Moist but well–drained
pH
Acid or Alkaline or Neutral

Position

Full sun Partial shade
Aspect
South–facing or West–facing or East–facing
Exposure
Exposed or Sheltered
Hardiness

Hardiness Ratings

All ratings refer to the UK growing conditions unless otherwise stated. Minimum temperature ranges (in degrees C) are shown in brackets

  • H1A: under glass all year (>15C)
  • H1B: can be grown outside in the summer (10 - 15)
  • H1C: can be grown outside in the summer (5 - 10)
  • H2: tolerant of low temperatures, but not surviving being frozen (1 to 5)
  • H3: hardy in coastal and relatively mild parts of the UK (-5 to 1)
  • H4: hardy through most of the UK (-10 to -5)
  • H5: hardy in most places throughout the UK even in severe winters (-15 to -10)
  • H6: hardy in all of UK and northern Europe (-20 to -15)
  • H7: hardy in the severest European continental climates (< -20)
H5

Colour & Scent

Season Stem Flower Foliage Fruit
Spring
Summer
Autumn
Winter

Botanical Details

Family
Ranunculaceae
Native to GB/Ireland
No
Foliage
Deciduous
Habit
Climbing
Potentially harmful
Skin irritant. Wear gloves and other protective equipment when handling. Pets (rabbits): Harmful if eaten. For further information and contact numbers regarding pets, see the HTA guide to potentially harmful plants
Genus
Clematis can be deciduous or evergreen shrubs or herbaceous perennials, mostly climbing by twining leaf-stalks, and often with showy flowers. Some have attractive fluffy seedheads in autumn
Name Status
Correct
Plant Range
China, Japan, Korea

How to Grow

Cultivation

Plant in moisture-retentive, well-drained soil, with the roots and base of the plant kept cool and shaded by other plants or a layer of pebbles at the base. Plant with the crown 5-8cm deep to encourage new shoots to grow from below ground level. Ideal for a trellis or garden obelisk. See clematis cultivation

Propagation

Propagate by softwood cuttings in spring, semi-ripe cuttings in early summer or layering

Suggested planting locations and garden types

  • City and courtyard gardens
  • Cottage and informal garden
  • Patio and container plants
  • Climber and wall shrubs
  • Wall side borders

Pruning

See clematis pruning: group two

Pests

May be susceptible to aphid, slug, snail or caterpillar damage on young growth

Diseases

May be susceptible to honey fungus (rarely), clematis wilt and clematis slime flux