Jackman’s clematis

Clematis ‘Jackmanii’

The original large-flowered clematis hybrid of 1862, with rich deep-purple velvet four-petalled saucer flowers through high summer. The signature clematis cultivar of British gardens for 160 years.

Hardiness ratings

Jackman’s clematis hardiness across the four zone systems
SystemRatingTemperature rangeHow to read it
USDA hardiness zone Zone 4–8 −34.4 °C to −6.7 °C Plant tolerates down to this zone
RHS hardiness rating H6 −20 °C to −15 °C Plant needs at least this level of cold tolerance
Canadian plant hardiness zone Zone 4–8 −29 °C to −1 °C Plant tolerates down to this zone
Australian (ANBG) zone Zone 2–6 −10 °C to 15 °C Plant tolerates down to this zone

Growing notes

  • Plant against trellises, fences, and shrubs — flowers July–September, the original large-flowered clematis still among the most widely planted
  • Pruning Group 3 — cut back hard to 30 cm each spring
  • More resistant to clematis wilt than later large-flowered hybrids
  • Vigorous but well-behaved — reaches 3–4 m

Pet caution: Jackman’s clematis is listed as potentially harmful to cats and/or dogs. Keep pets from grazing on it, and contact a vet if you suspect your animal has eaten some.

Categories

Related plants

Cross-check Jackman’s clematis against your zones

Reference

Jackman’s clematis on Wikipedia