Cardinal climber has bright red tubular flowers. A hummingbird’s long tongue can access the nectar deep inside the flower.
Ginger E. Long ©2024 HGIC, Clemson Extension
Overview of Cardinal Climber
When considering plants that attract hummingbirds, don’t forget vines! Many vines have tubular flowers that hummingbirds visit for nectar. One such vine is cardinal climber (Ipomoea x multifida). It can easily be grown from seed and produces bright red flowers from summer through fall.
The cardinal climber is an heirloom plant, meaning it has been passed down for several generations. Heirloom plants produce seeds that have the same characteristics as their parents. The seeds can be saved year after year.
How to Grow and Care for the Cardinal Climber
USDA Plant Hardiness Zones: It grows in all zones as an annual, but it is only cold hardy in zones 10 to 12.
Best soil: Plant it in moist, well-drained soil. If planting in a pot, use quality potting soil.
Sunlight: For best flowering, plant it in full sun to partial shade, ensuring it gets several hours of direct sun per day.
Watering: As it is a tropical vine, it grows best if watered regularly, receiving one inch of water per week.
Fertilizer: It requires little to no fertilizer. Fertilize as needed.
Pruning: The vines do not need pruning. Only prune to maintain the desired size.
Support: Provide a trellis, arbor, or fence for it to grow on. Plant it in a hanging basket and allow it to hang down.
Grow cardinal flower on a trellis or arbor. The flowers point up, making it easy for hummingbirds to feed.
Ginger E. Long ©2024 HGIC, Clemson Extension
How to Start Cardinal Flower from Seed
Seeds can be directly sown in the garden after all danger of frost has passed. They can also be started indoors 4 to 6 weeks before the last frost date.
Because the seeds are hard, they should be scarified before sowing. Use a pair of nail clippers to nick one side of the seed. Then, soak the seeds in water for up to 24 hours before sowing.
Planting depth: Cover seeds with ½ inch of soil.
Spacing: Leave 4 to 6 inches between seeds.
Days to Germinate: Expect seeds to sprout in 5 to 10 days.
Mature height: Vines will grow 8 to 10 feet tall.
Note: Seeds are poisonous to humans and animals when ingested.
CAUTION: Cardinal climber can reseed more than desired. To manage the number of seeds, remove the seed pods that can be reached when they are green. Dispose of the pods in the trash and do not compost them. Next spring, watch for seedlings and remove them when they are small.
Cardinal Climber vs. Cypress Vine
Cardinal climber is often mistaken for cypress vine (Ipomoea quamoclit). The cardinal flower’s red flowers are trumpet-shaped, and the leaves are not as fern-like as the cypress vine.
Ginger E. Long ©2024 HGIC, Clemson Extension
Cypress vine (Ipomoea quamoclit) has five-point star-shaped flowers and fine, fern-like foliage. It is closely related to the cardinal climber.
Barbara H. Smith ©2024 HGIC, Clemson Extension
