Moluccella laevis aka Bells Of Ireland

Moluccella laevis is an annual in the mint family. Most gardeners know it as bells of Ireland. Its native range runs from western Asia to Turkmenistan. Despite its name, it does not come from Ireland. The green bells help explain that common name. It also grows outside its native range in Europe and America.

Plants grow upright and branch from square, green stems. Garden plants reach about 2–3 feet (0.6–0.9 metres) tall. RHS gives an upper height of 3.3 feet (1 metre). They spread about 1–1.6 feet (0.3–0.5 metres) across. Small, sharp thorns grow on the stems. The stems have no scent. Light green leaves grow in opposite pairs. Each simple leaf has an egg shape and scalloped edges. The leaves lack hairs and reach about 2.5 inches long.

Long flower spikes give this plant its main garden interest. Large, pale green calyces surround the small flowers. These bell-shaped cups have white veins and crowd the spike. The true flowers are white or pale pink. They have two lips and a scent. Bloom dates vary between sources and growing sites. Chicago lists May through August; NC State lists July through September. RHS places flowering in late summer. The green cups later turn beige. NC State describes the fruit as a nut. Chicago lists birds and butterflies among its visitors.

Give plants full sun and moist soil that drains well. They can also cope with light shade and poor soil. Moderately fertile soil supports their best growth. They accept clay, loam, sand, and chalk soils. Acid, neutral, and alkaline conditions all suit them. Cool summers suit them better than hot, humid weather. Sources give different USDA ranges: Chicago lists 5–8, while NC State lists 2–11. RHS assigns the UK rating H4. Plants grow fast and reach full size within one year.

Use bells of Ireland in borders, containers, and cutting gardens. The spikes suit both fresh and dried flower work. Cut stems before seeds ripen when drying them. Hang them somewhere dry with good airflow. Cutting before seed formation also limits self-seeding. Stakes can help prevent stems from sprawling. Grow new plants from seed; outdoor sowing suits them well. They need no pruning and have few serious pest problems. Sources also report few disease problems, but summer heat and humidity can cause trouble.