Flowers

How to Plant Cardinal Climber: Timing, Spacing, Care & Bloom

Quick answer

Start indoors 4–6 weeks before last frost (WI/Clemson) or direct sow after frost when soil is warm. NC State: seeds poisonous if eaten (Low). Not cypress vine.

Cardinal climber at a glance
PlantStart indoors: 6–4 wk before last frost; Direct sow: last frost
SunFull sun; warm soil.
SpacingClemson: cover about ½ inch; space 4 to 6 inches.
Days to bloomBlooms mid-summer until frost (Wisconsin)
-7-6-5-4-3-2-1LF+1+2+3
■ Start indoors   ■ Plant out   ■ Harvest
Weeks relative to last frost (LF). Colored weeks show when our ZIP planner schedules each step.
Jump to

Updated

Not cypress vine: cardinal climber is Ipomoea × multifida (often listed as I. sloteri) — a hybrid related to cypress vine, not the same plant.

Safety: NC State poison severity Low — seeds poisonous if eaten. (NC Ipomoea × multifida)

Cardinal climber flowers
Cardinal climber (Ipomoea × multifida). Photo: Salicyna, Wikimedia Commons, CC BY-SA 4.0 (resized).

Sourced from university extension guides. For dates where you live, use the ZIP planting planner.

Planting timing

Wisconsin: start indoors 4 to 6 weeks before the last spring frost, or direct sow “after all danger of frost is past and the soil is warm.” Scarify and/or soak overnight. (WI cardinal climber) Clemson: direct sow after frost; or start indoors 4 to 6 weeks before the last frost date. (Clemson hummingbird gardening)

Depth and spacing

Clemson: cover about ½ inch; space 4 to 6 inches. Provide a trellis.

Sun, soil and water

Full sun; warm soil. Twining annual vine.

Care and bloom

Mid-summer to frost; bright red trumpets for hummingbirds (WI/Clemson/NC).

Pests and diseases

Cultural warmth and support first.

Related: ZIP planner · planting calendars

Frequently asked questions

When do I start indoors?

4–6 weeks before last frost (WI/Clemson).

Direct sow?

After frost when soil is warm (WI/Clemson).

Are seeds safe?

NC Low — poisonous if eaten.

Sources