Cardinal Climber, Ipomoea sloteri


Cardinal climber, Ipomoea sloteri.

Cardinal climber is a hybrid plant, an allotetraploid created by Logan Sloter of Columbus, Ohio who crossed (by hand pollination) 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 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, but the progeny could not be crossed with either of the parents or any other Ipomoeas. This hybrid, descended from this single plant, reproduces true from seed, with very few deviations from the parent. Initially called I. x multifida (and still often offered under that name), it is now correctly called I. sloteri.

Cypress vine, Ipomoea quamoclit, one of the parents of cardinal vine and its flower (inset).

Confusingly, in some areas it goes by the common name of cypress vine (also the common name of one parent plant), or other monikers including morning glory or hearts and honey vine. This frost tender annual heirloom 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 3-7 pairs plus one wider terminal lobe), almost resembling little palm leaves and giving a lacy appearance to the foliage. This vigorous, twining tropical plant 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.

The leaves of cardinal climber (L and C) and the more finely divided leaves of cypress vine, Ipomoea quamoclit (R).

A ruby-throated hummingbird feeds from a cardinal flower.

Cardinal vine begins blooming in mid-summer and continues until the plant is killed by frost. Like both parent species, cardinal climber produces vivid, bright red, trumpet-shaped flowers with yellow or white throats (although cypress vine may also have pink or white flowers). The five overlapping petals of the inch long flowers are flared at end (a salverform corolla), forming a pentagon shape (cypress vine flowers are more star-shaped) 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.

The flowers of cardinal vine (L) are trumpet-shaped with a pentagonal shape (LC) which reflexes back as the flower ages (RC) and finally sheds, leaving the developing fruit behind (R).

The irregularly-shaped dark brown seeds (magnified).

Flowers are followed by fruits which are ovoid capsules. Each rounded green capsule eventually dries to a papery brown cover over 2-4 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.

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 even be grown in a container (but may overwhelm any other plants in the container even if given a support to climb) or a hanging basket where the vines will eventually cascade back down after climbing upwards.

Cardinal vine grows quickly from a small plant (L), to cover a freestanding trellis (C) or on the side of a house (R).

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.

Cardinal climber is an annual propagated from seed. To enhance germination, scarify (nick with a knife or use sandpaper to abrade the hard exterior) the large seeds and/or soak them in warm water overnight before sowing. Seeds treated this way should germination in a week or two. This vine can be started indoors 4-6 weeks before the last frost, but like most plants in the morning glory family it doesn’t like to have its roots disturbed, so it is often sown directly in the ground after all danger of frost is past and the soil is warm. Place the seeds about a quarter inch deep in the soil and space 6-12” apart.

– Susan Mahr, University of Wisconsin – Madison

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  1. I have it growing up my mail box in Coastal North Carolina. It took a long time to bloom but is now beautiful. Labor Day and it finally has lots of blooms, and it was planted early May. Note the flowers are much smaller than morning glories and what it looks like on the seed packet.
    I do not think it would attach to a concrete wall unless you make some supports for it as it needs something to twist around. It grows very fast and I have to twist and direct it to keep it where I want it every morning, or it’s over the 6′ fence and up into the neighbor’s trees. Probably it can be trimmed to control size.
    I had 100% germination from a packet of seed, which I soaked 48 hours before planting. It definitely flowers better with lots of sunshine and the plants I transplanted from starter pots didn’t do well.

    Since it freezes off in the winter I presume it would not be considered invasive in Zone 7.

  2. Intrigued by the photo on the seed packet in a local store, soaked overnight and grew in paper cups. Transplanted to a trellis and a fence each w 75% direct sun (in Boise) they are vining like crazy but no flowers yet (8/8/18). Love the exotic leaves and that i can save the seeds!

  3. This does off completely in winter? Or is it invasive like morning glory?

  4. I noticed my cardinal flower is getting yellow leaves around the base. Also planted in May still has not bloomed but climbing well. What.could the problem be?

  5. Does anyone know if I move the pot into. The house before frost, will it winter indoors or die off any way??

  6. If you’re interested in growing Cardinal Climber from seed, google it and you’ll get many results for retailers selling the seed.

    My personal advice? Soak them for 2 days before planting. I’ve had the best luck doing it that way. Some seeds even start to sprout in the water. That’s OK. Plant them as usual.

  7. I am always amazed when I read that a plant that I have growing in my garden every year was developed in the 1800’s. I buy the plant already started but will try saving the seeds this summer and plant them next spring. It is a really attractive plant for a tall accent in my hummingbird/pollinator garden.

  8. Logan Slotter got such a beautiful reward for his patience. Has anyone seen seedlings for sale in Ozaukee county? It would be nice to try it for a year to see what it does!

  9. This was interesting. It was neat to learn about the cross pollination of the plants to make the cardinal climber. Without people to try these things there would be a lot fewer plants in the world. Thanks to them we have a lot of beautiful plants to enjoy and grow.

  10. I did not know that the Cardinal Climber was cross pollinated between a red morning glory and a cypress vine—interesting! I had not heard of the cypress vine. I planted Cardinal Climber from seed around the very long trunk of a very tall pine in a raised bed bordering my patio many years ago. I had a red/wht/blue theme. The Cardinal Climber was beautiful growing up the trunk–not too huge as semi-shady spot. The lacey leaves and delicate blossoms were just beautiful!

  11. Interesting article and beautiful photos. The morning glory hybrid info was news to me. It is nice to learn of a different climber.

  12. I did not know that the Cardinal Climber was hybridized from the morning glory, or that morning glories were native to Central and South America. Logan Sloter was a very patient man — working 11 years to create this specimen!

  13. It is nice to see that humming birds and butterflies are attracted to Cardinal Cllimber. Looks like a nice vine type plant.

  14. I like the idea that the cardinal climber grows up to 10 ft. long and also attracts hummingbirds. With that info I will be trying it next spring over an arbor in my garden

  15. Beautiful climber! Glad to learn how to save the seeds and how to help them germinate more readily in the spring

  16. Logan Slater was very patient and tenancious waiting eleven Years! Fascinating after that, one plant then produced 500 seeds. I like that the flowers attract hummingbirds and that the leaves are distinctly different. I really do not have a spot for this plant due to the deer and rabbits in my yard.

  17. I found out that Cardinal climber seeds are highly toxic if ingested. I am going to try this on my free standing trellis next year as I was not happy with the bean plant that was growing on it this year.

  18. I was not aware that there are plants that don’t like to have their roots disturbed, like morning glories.

  19. It states the seeds are highly toxic and the Cardinal Clumber is from the Morning Glory Family. Does that mean Morning Glory seeds are also toxic?

  20. I was happy to read the article, as I was hesitant to try growing one. Now I think next summer I have the perfect place for it. . I saw seeds in a garden store. In fact I may have seen small plants for sale. It really is a pretty and bright flower.

  21. Noce that it attracts humming birds. Also being an annual you can seed it in different places year to year.

  22. It takes an awful lot of patience to wait 11 years for a seed. I am unfamiliar with the plant and it would be a nice addition to my garden. The description as a climber or dense ground cover seems unique. The leaves are very distinctive.

  23. After reading this article, I believe that I may try to grow this in a container that I will put next to my pergola on my deck. I think that it would be easy to start inside and then just move outside when the weather warms up in the spring. I think it would be an interesting experience. I didn’t know of this plant, so this article was very informative.

  24. I like that it attracts the ruby throated hummingbird. I am always looking for more flowers for them. I like the palm looking leaves on this plant. I didn’t know it was a vigorous grower.

  25. I liked the idea of the Cardinal climber being so prolific of a vine, however, I do not like the fuss of having to knick/scar the seed to be able to germinate them. So many other vines would appeal to me more. So nice read, especially because I hail from Ohio and hearing that it was hybridized by a fellow Ohioan made me feel proud. Especially because the Ohio State bird is the Cardinal. I live on a lake in NE FDL Co. and have planted Cardinalis only to find that the first year is wonderful but it doesn’t survive the harsh winters we get.

  26. I believe I have tried growing this a few time and it did not grow well for me. Maybe not enough sun. I learned that is a cross between a red morning glory and cypress vine. Interesting how it took a while from 1897 till 1908 to produce a single seed.

  27. This may well be the answer to a perplexing problem. I have a block wall that is a bit dull in mid summer. Two questions; 1) where can I get seeds? and 2) does anyone have experience growing cardinal climber along block walls in full sun?

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