Overview of Cardinal Climber
Cardinal climber is an interspecific hybrid plant, an allotetraploid created by Logan Sloter of Columbus, Ohio who crossed red morning glory (Ipomoea coccinea) and cypress vine (I. quamoclit, as the pollen parent), both native to Central and South America. He made this cross every season starting in 1897, but all of the few specimens produced were absolutely seedless. It took eleven years of crossings before one of the hybrid plants produced a single seed in 1908. When planted the following year, that single seed grew into a plant that produced about 500 seeds. The progeny could not be successfully crossed with either of the parents or any other Ipomoea species, but reproduces true from seed. Initially called I. x multifida (and still often offered under that name), it is now called I. sloteri.
Confusingly, this species sometimes goes by the common name of cypress vine, which is also the common name of one parent species. It is also called morning glory and hearts and honey vine.
This frost tender annual vine in the morning glory family (Convolvulaceae) has been grown as an ornamental for over 100 years both for its attractive foliage and prolific flowers.
The alternate leaves of cardinal climber are halfway between the finely divided, feathery leaves of cypress vine and the entire, heart-shaped leaves of red morning glory. The triangular, medium green leaves are multiply divided into numerous deep, narrow lobes of varying numbers (usually 3 to 7 pairs plus one wider terminal lobe), almost resembling little palm leaves and giving a lacy appearance to the foliage. This vigorous, twining tropical vine grows up to 10 feet long, growing slowly under cool conditions, then rapidly growing and blooming in hot, humid weather. The slender, flattened stems intertwine and tangle amongst themselves or whatever they are rambling up or over.
Cardinal vine begins blooming in mid-summer and continues until being killed by frost. Like both parent species, cardinal climber produces vivid, bright red, trumpet-shaped flowers with yellow or white throats. The five overlapping petals of the inch long flowers are flared at end (a “salverform” corolla), forming a pentagon shape from which the five white to yellow stamens and a single 1 to 2-lobed style with globular stigma protrude.
The nectar-producing flowers are attractive to ruby throated hummingbirds, as well as bees and some butterflies, and close up at night.
Flowers are followed by fruits which are ovoid capsules. Each rounded green capsule eventually dries to a papery brown cover over 2 to 4 hard seeds. The irregularly-shaped mature dark brown to black seeds resemble a typical morning glory seed. To save seeds to plant the following year, allow the seed pods to dry on the plants and collect the brown pods before they split open and release the seeds. It will not reseed in cold climates (but will readily in warmer areas). Seeds are highly toxic if ingested.
Landscape Use of Cardinal Climber
Place cardinal climber near a trellis, arbor or other structure it can climb. Or use it as a dense groundcover or plant it near plants that will decline by mid-summer (such as breadseed poppy) so it will scramble over and cover the other plants. Cardinal climber can be grown in a container, but it may overwhelm any other plants in the container even if given a support to climb. In a hanging basket, the vines will eventually cascade back down after climbing upwards.
Grow cardinal climber in full sun in any well-drained soil. Although it will tolerate dry soil, provide regular water for the best growth, and fertilize only if the soil is very poor. The vines can be trimmed but do not need regular pruning and the flowers do not need deadheading. This plant has no significant diseases or insect pests, but rabbits and deer may feed on them.
Propagating Cardinal Climber
Cardinal climber is an propagated from seed. To enhance germination, scarify (nick with a knife or use sandpaper or a file to abrade the hard exterior of the seed coat) the large seeds and/or soak them in warm water overnight before sowing. Seeds treated this way should germination in a week or two.
Cardinal climber can be started indoors 4 to 6 weeks before the last spring frost, but like most plants in the morning glory family it is vigorous enough that it is often sown directly in the ground after all danger of frost is past and the soil is warm. Plant the seeds about a quarter inch deep and space 6 to 12 inches apart.
Author: Susan Mahr, University of Wisconsin—Madison
Reviewers: Bruce Spangenberg, Horticulture Outreach Specialist, Allen R. Pyle, Horticulture Outreach Specialist, UW—Madison Extension
Revised: May 2026
