By late summer my bare 8 ft (2.4 m) back-fence trellis was green from the ground to the top rail, with red blooms poking through every gap. That whole wall of vine started as a few soaked seeds I poked into the soil right after the last frost that spring. The cardinal climber growth rate is fast, and one warm season is all it needs to fill a support like mine end to end.
Yes, cardinal climber is a genuinely fast growing annual vine. Once your soil warms up and nights stay mild, the twining stems take off and grab any support within reach. You can watch your vine gain a few inches in a single week during the heat of summer. The growth feels slow at first, then it speeds up once the roots settle in and the days get long.
NC State describes it as a rapid-growing annual with slender stems that twine their way upward. The plant does little above ground until warm weather arrives. Then it shifts gears in a hurry. Your vine will wrap around strings, wire, and thin posts on its own, so you rarely need to tie it up by hand. That self-climbing habit is part of why it covers ground so fast once it gets going.
The timeline is short for a vine this size. From cardinal climber seed to bloom you should expect about 12 to 14 weeks. That means a plant you sow in spring will flower by mid to late summer in most gardens. You get foliage first, then the small scarlet trumpets follow as the days warm and the vine reaches for the light.
Because it runs through its whole life in one season, the vine puts all that energy into climbing fast. It reaches its full mature height of about 8 to 15 feet (2.4 to 4.6 m) before the first fall frost cuts it down. You get a tall, dense screen the same year you plant the seeds, which is rare for something that climbs this high. A perennial vine would take two or three years to cover the same span.
Give that quick growth a tall support from day one. Set up your trellis, arbor, or string before your vine has anything to climb, since the stems will sprawl across the ground if they find nothing to grab. A support that reaches at least 8 feet (2.4 m) lets your plant show what it can do. Stretch jute twine or netting up a fence, and the vine will follow it on its own within a couple of weeks of warm weather.
In a short-season area, start your seeds indoors 4 to 6 weeks before your last frost date. This gives you flowers earlier and a longer show before cold weather ends the run. Soak the hard seeds overnight first so the tough coat softens, and they sprout faster once they hit warm soil outside. Move your seedlings out only after nights stay above 50°F (10°C), since chilly soil stalls the early growth and wastes the head start you worked for.
So plan for a vine that climbs hard and finishes the season tall. Sow it in spring, hand it a sturdy 8 to 15 foot (2.4 to 4.6 m) support, and keep the roots watered through the hot months. You will have a screen of red blooms and ferny leaves by late summer, every year, from seed.
Read the full article: Cardinal Climber: Grow Guide and Care Tips
