Ornamental · Lamiaceae
Bells of Ireland
Moluccella laevis
Tall green spires of bell-shaped calyces that love 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 gets its name from the ring of green, bell-shaped calyces stacked up each tall stem, with the tiny real flowers tucked away inside. And despite the name? It's actually from the eastern Mediterranean to western Asia, not Ireland at all. Gardeners grow it as a cool-season annual for its unusual color and shape, both out in the bed and later on in a vase.
This is a plant that wants cool growing weather and really doesn't get along with heat and humidity. It shoots up fast, throwing out spikes of 2 to 3 feet (60 to 90 cm) in just one season, then blooms from mid-summer into fall. One heads-up: pairs of small, sharp spines hide under each green bell, so grab some gloves before you cut a stem.
Florists are just as into it as gardeners are. The green calyces keep their color once they're cut, and they dry well for lasting arrangements, which is why you'll spot the stems in bouquets long after the garden's gone quiet for the year.
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 those tall spikes anywhere it gets windy.
Light
Give it full sun for the strongest, straightest spikes, though it'll take a bit of partial shade too. Too much shade, though, and you'll end up with weak, leaning stems and fewer of those green bells.
Water
Keep the soil evenly moist all the time, and water through any dry spell so it never bakes. Since this plant really doesn't like heat, steady moisture in summer is one of the best ways to keep it happy.
Soil
Plant it in loose, moderately fertile, well-drained ground that holds even moisture. It'll put up with poorer soil as long as drainage stays sharp, and a pH anywhere from 6.0 to 7.5 works just fine.
Temperature
It's a cool-weather plant that does best between roughly 39°F and 81°F (4°C to 27°C). Once the heat and humidity of high summer roll in, it starts to slow down and fade.
Humidity
Regular outdoor air is totally fine, so there's no number to chase. Humid, muggy heat is the real enemy here, so give the plants some room and keep air moving around them.
Feeding
A balanced general-purpose fertilizer once a month through the growing season is plenty. Don't overdo it, though, since soft, overfed growth tends to flop more easily.
Pruning
Cut the flower spikes for fresh or dried use, and deadhead before the seed sets if you want to keep the self-sowing in check. In windy spots, those tall spikes usually need a stake to stay upright.
Size & spacing
Expect plants to hit 2 to 3 feet (60 to 90 cm) tall. Set them about 12 to 18 inches (30 to 46 cm) apart, which is close enough that the neighboring stems help hold each other up.
When to plant
Bells of Ireland is built for cool weather and just wilts in the heat, so timing is pretty much everything. Start seed indoors in late winter, move plants out a few weeks before the last frost once nights stay above 40°F (4°C), and the spikes will bloom 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
Almost all the trouble with this plant comes down to two things: summer heat and the height of its own spikes. Catch the early signs below and you can step in before a little setback turns into a spoiled display.
Plants giving up right when summer gets hot
Here's the thing: Bells of Ireland is a cool-season plant, so heat plus humidity is exactly what wears it out, and that's when the spikes fade and blooming tails off. Want it to keep going? Pop it in full sun where the air can move, keep the soil evenly moist, and sow it early so most of the flowers happen before summer really cranks up.
Fix:
- Site in full sun with good air circulation
- Keep soil evenly moist during heat
- Sow early so plants bloom before peak summer heat
Sowed a month ago and still nothing coming up
Tray still looking empty? Slow germination usually just means the seed went in too deep or sat at the wrong temperature. The seed needs light to wake up, so barely cover it and give it warm days around 80°F to 86°F (27°C to 30°C) with cooler nights near 60°F (16°C). After that, it's a waiting game, because even when you've done everything right those seedlings can take up to a month to show up.
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
Those tall stems flopping over after rough weather
Those spikes get tall and top-heavy, so it doesn't take much, just a gust or a good downpour, to bend them over, and the tallest ones always go first. The fix is easy: stake them early if the spot's exposed, and pick somewhere sheltered if you can. Planting them about a foot apart lets them lean on each other, and going easy on rich soil keeps the growth from getting soft and floppy.
Fix:
- Stake taller spikes
- Provide a sheltered, less windy location
- Space plants about a foot apart for mutual support
Toxicity
Good news if you've got pets or kids around, because this plant is not considered poisonous to animals or people. The only real hazard is physical, not chemical: pairs of sharp little thorns hide beneath each green bell, so wear gloves whenever you handle or cut the stems.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
No need to worry about cats, since there aren't any poisoning reports and it isn't listed as toxic. The only thing to keep an eye on is the little stem spines, which could give a nosy cat a prick on the mouth.
Dogs None
Dogs are totally fine around it, because nothing in the plant counts as poisonous. If one chews a stem, it'll probably just feel a sting from the hidden thorns, not anything worse.
Horses Safe
Horses have nothing toxic to worry about here. Honestly, the sharp spines under each calyx make it a pretty unappealing snack anyway.
Rabbits Safe
Rabbits won't get poisoned by it, no problem there. The prickly stems usually put them off before they get very far.
Livestock Safe
Grazers like cattle, goats, and sheep have no toxin to deal with here. Most of them steer clear of the spiny spikes on their own anyway.
Birds Safe
Backyard birds can hang out in the same garden no problem, since nothing in the plant is known to hurt them.
People Safe
There's no poisoning risk for people either. Just grab some gloves before you cut stems, because the thorns hiding under the green bells are sharp enough to actually 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
There are only a couple of named selections out there alongside the wild species, each picked for one particular trait. These are the ones worth knowing about.
Pixie Bells
It's a compact pick with shorter, sturdier stems that stand up way better and rarely flop like the regular species does.
Long Spike
This one's grown for its extra-long flower spikes, which is exactly what cut-flower arrangers tend to want.
How to propagate
Bells of Ireland is grown from seed, and the seed itself has a few quirks you'll want to get right before you sow.
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.
Start it from seed indoors 8 to 10 weeks before your last frost, or just sow it straight outside a few weeks before. Barely cover the seed since light helps it sprout, and give it warm days around 80°F to 86°F (27°C to 30°C) with cooler nights near 60°F (16°C). You'll need some patience, because germination can take up to a month, but then it blooms that same season from mid-summer into fall, and it often drops seed and comes back on its own the next year.
Myths
Bells of Ireland comes from Ireland.
Funny enough, the name's a bit of a red herring. It's actually native from the eastern Mediterranean across to western Asia and India, nowhere near Ireland, and the name probably just comes from the green color of those bell-shaped calyces.
The seed needs a spell in the fridge before it'll come up.
You'll see guides telling you to chill the seed first, but the research doesn't really back that up. What actually matters is surface sowing with light and the right temperatures, not giving it a stint in the cold.