Culture
Best grown in evenly moist, rich, well-draining soil in full sun. Tolerant of some shade, but will not produce as showy of a floral display. Start seeds indoors 4-6 weeks before the average last frost date. This is particularly recommended for climates with shorter growing season. Seeds are slow to germinate. Scarify the seeds and soak them for several hours to speed up germination. Only plant outdoors once the threat of frost has completely past. In climates with longer growing seasons, scarified and pre-soaked seeds can be planted directly in the garden once the threat of frost has past and the soil begins to warm. Will reseed readily in warmer climates and may become problematic if the seedlings are left unchecked.
Noteworthy Characteristics
Ipomoea × multifida, commonly known as cardinal climber, is an annual twining vine that results from the crossing of two Ipomoea species: I. quamoclit (cypress vine) and I. coccinea (scarlet morning glory). Mature vines can reach up to 15' tall and around 1' wide. The deeply dissected, finely textured foliage can reach up to 3" long and 2" wide. The bright red, outward-facing, 2" long tubular flowers are held singly or in loose clusters of 2-5 blooms. The flowers are highly attractive to hummingbirds. This plant is a diploid hybrid, meaning that one half of each of the parent species chromosomes are present in the hybrid. It can be distinguished from the very similar I. × sloteri by its smaller flowers and fewer, more narrow leaf lobes.
Genus name comes from the Greek words ips meaning "worm" and homoios meaning "resembling", in probable reference to the sprawling underground roots of plants in this genus. On the other hand, some experts suggest the genus name is in reference to the worm-like twining plant habit.
The hybrid name multifida means "highly divided", in reference to the dissected foliage.
The common name cardinal climber refers to the color of the blooms and the climbing habit of this plant.
Problems
No major pest or disease problems of note. Can reseed readily in warmer climates and may become problematic if the seedlings are left unchecked.
Uses
Requires a trellis, arbor, or other structure to climb. Use as a vertical accent in sunny mixed borders or patio plantings. Can be grown in a large container.