Flowers

How to Grow Bells of Ireland: Planting, Spacing, Care & Bloom

Quick answer

Start indoors 8 to 10 weeks before last frost (NC/WI). Direct sow a few weeks before last frost (NC). Transplant when nights stay above about 40°F (WI/MU).

Bells of ireland at a glance

PlantStart indoors: 10–8 wk before last frost; Direct sow: 4–2 wk before last frost
SunFull sun; well-drained, consistently moist, moderately fertile soil (NC).
SpacingWI space about 1 ft.
Days to bloomBlooms summer to fall (NC State)
-11-10-9-8-7-6-5-4-3-2-1LF+1+2+3
■ Start indoors   ■ Plant out   ■ Harvest
Weeks relative to last frost (LF). Colored weeks show when our ZIP planner schedules each step.
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Updated

Bells of Ireland (Moluccella laevis) — cool-season / half-hardy annual. Tiny stem spines — handling caution, not a poison label.

Bells of Ireland flowers
Bells of Ireland (Moluccella laevis). Photo: HelloMojo, Wikimedia Commons, CC BY-SA 3.0 (resized).

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

Planting timing

NC State: sow outdoors a few weeks before the last frost date, or start indoors about 8 to 10 weeks before last frost — plants often do best started outdoors. Warm-winter climates may sow in fall. (NC State Moluccella) Wisconsin: indoors 8 to 10 weeks before last frost; barely cover (light helps); transplant once nights are above 40°F. (Wisconsin bells of Ireland) Purdue HO-14 lists 8 weeks before last frost. Planner: Start indoors last frost −10 to −8; Direct sow last frost −4 to −2 (labeled paraphrase of NC “a few weeks”).

Depth and spacing

Barely cover seed. WI space about 1 ft. NC: height 2–3 ft; width 1–1.5 ft.

Sun, soil and water

Full sun; well-drained, consistently moist, moderately fertile soil (NC). Poor performance in hot humid summers (NC/WI). Stake taller spikes in wind.

Care

Cut stems before seed ripening for dried arrangements; hang in a dry airy place (NC/WI). Self-seeds if stalks are left (WI).

Bloom

Summer spikes; calyces attractive into late summer (NC). Fresh or dried cut flower.

Pests and diseases

NC: no serious diseases or insect pests. Hot humid summers are the main cultural problem.

Related: ZIP planner

Frequently asked questions

When do I start bells of Ireland indoors?

8–10 weeks before last frost (NC/WI).

Can I direct sow?

Yes — a few weeks before last frost (NC), or when soil is about 50–60°F (MU).

Good for drying?

Yes — cut before seed ripening and hang dry (NC/WI).

Sources