The Lady Slipper newsletter of the Kentucky Native Plant Society has been published since the Society’s founding in 1986. We occasionally feature an article from a past issue. This one, about a rare, and threatened, native vine, Clematis crispa, commonly known as Blue Jasmine or Swamp Leather-Flower, first appeared in the summer of 2013, Vol. 28, No. 2. If you would like to see other past issues, visit the Lady Slipper Archives, where all issues from Vol. 1, No. 1, February 1986 to Vol. 34, No. 1, Winter/Spring 2019 (after which we moved to this blog format) can be found.
Western Kentucky’s Swamp Leather-flower
Robert Dunlap, OKNP Volunteer
© Bob Dunlap
© Bob Dunlap
One of the plants I look for every spring in western Kentucky is Clematis crispa, commonly known as Blue Jasmine or Swamp Leather-Flower. C. crispa is listed as “Threatened” by the Office of Kentucky Nature Preserves and is only known from the four western counties along the Mississippi and Ohio Rivers – Ballard, Carlisle, Hickman and Fulton. It occurs in a few counties across the rivers in southern Illinois and western Missouri and becomes more common as you head into the southern states.
As its name implies, this native clematis likes to grow in wetlands, floodplains and swamps. All of the sites where I’ve found this plant growing in Ballard and Carlisle counties are flooded for some portion of the year when the rivers decide to overflow their banks. In addition to enjoying getting its feet wet, C. crispa prefers a bright location and is usually found competing for sunlight along with all the other vine species that like to grow in swampy conditions. The stems of this herbaceous vine grow to a length of 6- 10 feet and the plants die back to ground level each winter. The flowers consist of four sepals (no petals) that curl backwards resulting in an urn-like appearance.
© Bob Dunlap
Finding this plant in the field is a matter of being in the right place at the right time. Searching for the purple-blue flowers before the neighboring vines have put out all of their foliage affords the best chance for success. Another option that requires good eyesight is to search for the distinctive seed pods, sometimes referred to as “Devil’s Darning Needles” in the fall.
Two additional native clematis species that can be found in western Kentucky include C. pitcheri (Bluebill) and C. virginiana (Virgin’s Bower). Differentiating C. crispa from C. pitcheri is best accomplished by examining the undersides of the leaves. C. pitcheri exhibits a prominent raised network of veins which are absent on C. crispa.
A quick internet search turned up several native plant nurseries where Swamp Leather- Flower can be purchased. From the planting advice given on these sites it apparently does well when grown in containers and I’m guessing it would make a nice addition to an outdoor pond or water garden