Often mistaken for Ipomoea quamoclit ("Cypress Vine"), this closely-related plant is a cross between Ipomoea coccinea ("Red Morning Glory") and I. quamoclit ("Cypress Vine") with slightly coarser leaves. The real Cardinal Climber has leaves that are more palmate than cypress vine and more ferny than morning glory. It's quite confusing, especially since many seed companies label them wrongly. The flowers are small, red, and tubular. They are absolute hummingbird magnets.
This above picture may actually add to the confusion about identifying the cardinal climber because I have it growing with a real morning glory. The large leaves you see are from the morning glory. The cardinal climber blooms much earlier than the Heavenly Blue morning glories. However, they play out and die before the MG's. They are quite easy to grow from seed and will readily climb any structure you put them on. The real Cardinal Climber is not invasive and the seeds have been sterile in my experience. I have planted them every year for a number of years now and have yet to get even one volunteer plant the following year. This is why I much prefer planting these to planting its parents - red morning glory and cypress vine. Give this easy and well-behaved plant a chance and you won't regret it. Just be sure you get the real thing or you will be stuck with an invasive, though beautiful, substitute.