Ornamental · Lamiaceae
Bells of Ireland
Moluccella laevis
Tall green spires of bell-shaped calyces that favor cool weather and dry beautifully for the vase.
Full sun
39–81°F · 4–27°C
USDA 2–11
24–35 in · 60–90 cm
Overview
Bells of Ireland is named for the rings of green, bell-shaped calyces that stack one above the next up each tall stem, each shell-like cup cradling a tiny true flower at its center. The green is the whole point, since the calyces, not petals, carry the color, and they sit so densely that the stalk reads as a single green spire. Despite the name the plant comes from the eastern Mediterranean to western Asia, and it is grown as a cool-season annual.
The plant climbs fast, sending up smooth, square-sided stems to 2 to 3 feet (60 to 90 cm) in one season before the bells open from mid-summer into fall. Run a hand down a stem with care, because pairs of small, sharp spines hide just below each green bell, set close against the stalk. Those bristling little thorns are easy to miss until they catch a finger, so gloves earn their place at cutting time.
The green calyces are firm and papery to the touch, and that texture is why they last. Cut stems hold their color and dry well for lasting arrangements, the bells stiffening as they age rather than wilting, so the green spikes keep their shape long after they leave the plant.
Care
The short version: full sun and cool growing weather, soil kept evenly moist but never soggy, a balanced feed through the season, and a stake for the tall, bell-laden spikes in any windy spot.
Light
It wants full sun to push up the strongest, straightest spikes packed with bells, though it takes a little partial shade. In heavier shade the stems thin and lean, and far fewer of the green bells form along them.
Water
The soil stays evenly moist at all times, with a drink through any dry spell so the stems never bake. The plant dislikes heat, so steady summer moisture keeps the green firm and the bells forming.
Soil
It roots into loose, moderately fertile, well-drained ground that holds even moisture. Poorer soil suits it too as long as drainage stays sharp, and a pH anywhere from 6.0 to 7.5 is fine.
Temperature
This cool-weather plant holds its crisp green best between roughly 39°F and 81°F (4°C to 27°C). Once the heat and humidity of high summer set in, the stems soften and the bells stop forming.
Humidity
Ordinary outdoor air is fine, so there is no level to chase. Humid, muggy heat is the real enemy, so the plants want room and air sliding past the stems.
Feeding
A balanced general-purpose fertilizer once a month through the growing season is plenty. Heavy feeding only swells soft, weak stems that bend and flop under their own bells.
Pruning
The bell-covered spikes are cut for fresh or dried use, and deadheading before seed set reins in self-sowing. In windy spots the tall stems usually need a stake to stand straight.
Size & spacing
The stems reach 2 to 3 feet (60 to 90 cm) tall. Set about 12 to 18 inches (30 to 46 cm) apart, close enough that neighboring stalks lean together and hold each other up.
When to plant
Bells of Ireland is built for cool weather and softens in the heat, so timing shapes how the green spikes form. Start seed indoors in late winter, move plants out a few weeks before the last frost once nights hold above 40°F (4°C), and the bells climb the stems from mid-summer into fall.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Sow: 8 to 10 weeks before the last spring frost; barely cover seed as light aids germination, which can be slow (up to a month).
- Plant: A few weeks before the last frost, or transplant once night temperatures stay above 40°F (4°C).
- Harvest: Blooms mid-summer to fall (July to September); cut stems for fresh use, or before seed ripens for drying.
Hardiness
USDA hardiness zones: 2–11
Temperature: down to -46°C
Troubleshooting
Most trouble with this plant traces back to two things: summer heat and the height of its own bell-laden spikes. Read the early signs below and you can step in before a small setback marks the green spires.
Green spires losing their color and crispness as summer heat builds
Bells of Ireland is a cool-season plant, and once heat and humidity press in together, the green spikes lose their crisp, upright firmness and the bells stop forming. The tall stems soften and the color dulls as flowering slows. Full sun with air sliding freely past the stems helps, soil kept evenly moist steadies them through the heat, and an early sowing brings the green spires on before the worst of summer.
Fix:
- Site in full sun with good air circulation
- Keep soil evenly moist during heat
- Sow early so plants bloom before peak summer heat
Soil still bare of green shoots a full month from sowing
Slow germination comes from seed pressed too deep into the soil or sitting at the wrong temperature. The small seed sprouts only when light reaches it, so a bare dusting of soil over it works best, with warm days around 80°F to 86°F (27°C to 30°C) and cooler nights near 60°F (16°C). Even then the first green shoots can be slow, taking up to a month to break the surface.
Fix:
- Barely cover seed as light aids germination
- Provide warm day temperatures around 80 to 86°F and cooler nights near 60°F
- Be patient; germination can take up to a month
The tallest bell-lined stems keeling over in rough weather
Each spike loads its weight near the top, where the green bells crowd thickly along the stem, so the tall, top-heavy stalks lever over in wind or under the weight of rain, and the longest lean first. A stake set early holds the stem straight, and a sheltered position spares it the gusts. Stems spaced about a foot apart lean their shoulders together, and lean soil keeps the stalks firm instead of soft and pliable.
Fix:
- Stake taller spikes
- Provide a sheltered, less windy location
- Space plants about a foot apart for mutual support
Toxicity
For households with pets and children the news is reassuring, since this plant is not considered poisonous to animals or people. The one real hazard is physical, not chemical: pairs of sharp little thorns sit beneath each green bell, pressed close to the stem, so wear gloves whenever you handle or cut the stalks.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
No reports tie this plant to poisoning in cats, and it carries no toxic listing. The fine spines hidden along the stems are the only thing to mind, since a curious cat could prick its mouth on them.
Dogs None
Nothing in the plant is poisonous to dogs. A chewed stem might sting from the small thorns tucked beneath the bells rather than cause any real harm.
Horses Safe
Horses face no toxic risk from this plant. The sharp spines set under each green calyx make it a prickly, unappealing mouthful in any case.
Rabbits Safe
The plant will not poison rabbits. The bristly, spined stems usually put them off before they nibble much.
Livestock Safe
Cattle, goats, and sheep meet no toxin in this plant. Most avoid the stiff, spiny spikes of their own accord.
Birds Safe
Garden birds share the planting safely, since no part of it is known to harm them.
People Safe
The plant poses no poisoning risk to people. Gloves are still worth it at cutting time, because the small thorns hidden beneath the green bells are sharp enough to draw blood.
Pairs of small thorns or spines hide below each calyx along the stems and are sharp to the touch; wear gloves when handling or harvesting.
Varieties
Only a couple of named selections sit alongside the wild species, each differing in the stems and the spikes themselves. These two are worth a closer look.
Pixie Bells
A compact selection whose shorter, sturdier stems stand stiff and upright, rarely bowing or flopping the way the species does.
Long Spike
Grown for its extra-long flower spikes, with the green bells running farther up each stem, the form cut-flower arrangers reach for.
How to propagate
Bells of Ireland grows from a small seed, and that seed has a few quirks worth getting right before it goes into the soil.
SeedModerate
Sow indoors 8 to 10 weeks before last frost, or outdoors a few weeks before last frost; often self-seeds in the garden. · Germination can take up to a month; plants bloom the same season from mid-summer to fall.
Sow the small seed indoors 8 to 10 weeks before the last frost, or directly into the ground a few weeks before. Press it only into the surface, since light triggers sprouting, and hold warm days around 80°F to 86°F (27°C to 30°C) with cooler nights near 60°F (16°C). The first green shoots can take up to a month to surface. From there the stems climb and stack their bells, blooming that same season from mid-summer into fall, and the plants often drop seed and return the next year.
Myths
Bells of Ireland comes from Ireland.
The name misleads. The plant is native from the eastern Mediterranean across to western Asia and India, nowhere near Ireland, and the common name almost certainly points to the green color of its bell-shaped calyces.
Chilling the seed beforehand is the only way to make it germinate.
Some guides call for chilling the seed first, but the research does not bear it out. Surface sowing with light and the right temperatures is what actually matters, not a spell in the cold.