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Ranunculaceae FAMILY

Clematis hirsutissima

Clematis hirsutissima

Edibility
0/5
Medicinal
2/5

Safety & Hazards

Although no reports of toxicity have been seen for this species, some if not all members of this genus are mildly poisonous. The toxic principle is dissipated by heat or by drying[1].

Cultivation Details

HabitDeciduous Perennial
Growth—

Clematis hirsutissima is native to the temperate zone of the Rocky mountains in western N. America, where it can be found at elevations up to 2,500 metres. A moderately cold-tolerant plant, when fully dormant it can withstand temperatures down to about -20°c[2] Succeeds in any fertile well-drained soil in a sunny position[3]. Prefers a deep moist soil with its roots in the shade[4, 5]. Dislikes poorly-drained heavy clay soils, but grows well in clay if grit is added for drainage[4, 5]. Dislikes light sandy soils[4]. Does well on chalk[6, 3]. Succeeds in acid as well as alkaline soils[5]. When planting out, in order to avoid the disease 'clematis wilt', it is best to plant the rootball about 8cm deeper in the soil. This will also serve to build up a good root crown of growth buds[5]. Plants seem to be immune to the predations of rabbits[3]. A greedy plant, inhibiting the growth of nearby plants, especially legumes[7].

Propagation

Seed - best sown as soon as it is ripe in a cold frame[8, 5]. Sow stored seed as soon as it is obtained in a cold frame. Pre-soak the seed for 12 hours in warm water and remove as much of the tail and outer coat as possible[8]. A period of cold stratification is beneficial[8]. The seed germinates in 1 - 9 months or more at 20°c[8]. Prick out the seedlings into individual pots when they are large enough to handle and grow them on in a cold frame for the first winter. Plant out in late spring or early summer, after the last expected frosts. Internodal cuttings of soft to semi-ripe wood, late spring in sandy soil in a frame[5]. Layering of old stems in late winter or early spring[5]. Layering of current seasons growth in early summer[5]. Cite as: Temperate Plants Database, Ken Fern. temperate.theferns.info. 2026-02-20. <temperate.theferns.info/plant/Clematis+hirsutissima>

Pollinators

Bees, Flies

References

  1. [1]A Colour Atlas of Poisonous Plants. — Frohne. D. and Pfänder. J. · Wolfe · 1984 · ISBN 0723408394 ↩︎Brilliant. Goes into technical details but in a very readable way. The best work on the subject that I've come across so far.
  2. [2]Clematis - The Genus — Grey-Wilson. C. · B. T. Batsford. London. · 2000 · ISBN 0-7134-7659-1 ↩︎An excellent and well illustrated concise guide to all the known specis of Clematis.
  3. [3]Perennial Garden Plants — Thomas. G. S. · J. M. Dent & Sons, London. · 1990 · ISBN 0 460 86048 8 ↩︎A concise guide to a wide range of perennials. Lots of cultivation guides, very little on plant uses.
  4. [4]Trees and Shrubs Hardy in Great Britain. Vol 1 - 4 and Supplement. — Bean. W. · Murray · 1981 · ISBN - ↩︎A classic with a wealth of information on the plants, but poor on pictures.
  5. [5]The New RHS Dictionary of Gardening. 1992. — Huxley. A. · MacMillan Press · 1992 · ISBN 0-333-47494-5 ↩︎Excellent and very comprehensive, though it contains a number of silly mistakes. Readable yet also very detailed.
  6. [6]RHS Dictionary of Plants plus Supplement. 1956 — F. Chittendon. · Oxford University Press · 1951 · ISBN - ↩︎Comprehensive listing of species and how to grow them. Somewhat outdated, it has been replaced in 1992 by a new dictionary (see [ 200 ]).
  7. [7]How to Enjoy your Weeds. — Hatfield. A. W. · Frederick Muller Ltd · 1977 · ISBN 0-584-10141-4 ↩︎Interesting reading.
  8. [8]Growing from Seed. Volume 4. — Bird. R. (Editor) · Thompson and Morgan. · 1990 · ISBN - ↩︎Very readable magazine with lots of information on propagation. A good article on Yuccas, one on Sagebrush (Artemesia spp) and another on Chaerophyllum bulbosum.
  9. [9]A Field Guide to Rocky Mountain Wildflowers — Craighead. J., Craighead. F. and Davis. R. · The Riverside Press · 1963 · ISBN 63-7093 ↩︎Excellent little pocket guide to the area, covering 590 species and often giving details of their uses.
  10. [10]Native American Ethnobotany — Moerman. D. · Timber Press. Oregon. · 1998 · ISBN 0-88192-453-9 ↩︎Very comprehensive but terse guide to the native uses of plants. Excellent bibliography, fully referenced to each plant, giving a pathway to further information. Not for the casual reader.