Bells of Ireland

A striking annual with tall spikes of shell-shaped green calyces that surround tiny white flowers, prized by floral designers. Seeds require cold stratification and can be slow to germinate, so start early indoors or direct sow after last frost. The dramatic vertical stems dry beautifully and add architectural interest to arrangements.

Cold-stratify seeds in the refrigerator for 2 weeks before sowing—this dramatically improves germination. Sow seeds on the surface of moist compost indoors 8-10 weeks before the last frost. Do not cover seeds, as light aids germination. Keep at 55-65°F (13-18°C). Germination is notoriously slow and uneven, taking 14-28 days. Be patient and keep the soil consistently moist. Alternatively, direct-sow outdoors in early spring while the soil is still cool, which provides natural stratification.

Bells of Ireland requires patience, as the seeds have specific germination requirements. Refrigerate seeds for two weeks before sowing to provide cold stratification. Sow indoors 8-10 weeks before the last frost, pressing seeds onto the surface of moist compost—they need light to germinate. Germination is slow and erratic, taking 2-4 weeks at 55-65°F (13-18°C).

Transplant seedlings outdoors after the last frost, spacing 12 inches apart in full sun. These tall plants (24-36 inches) benefit from staking or the support of neighboring plants in a cottage-garden border. Pinch out the growing tip when plants are 6 inches tall to encourage branching and more flower spikes.

Bells of Ireland thrives in moderately fertile, well-drained soil and tolerates light shade. Water consistently during active growth but avoid waterlogging. The green bell-shaped calyces develop along the stem from the bottom upward, with tiny white fragrant flowers nestled inside each bell. The display lasts for weeks, and the calyces remain attractive even after the true flowers have dropped.

Bells of Ireland provides unique vertical green accents in mixed borders and cutting gardens. Plant alongside bold-colored flowers like zinnias, snapdragons, and dahlias, where the green bells provide a cooling contrast. They combine beautifully with purple larkspur and blue delphinium for sophisticated arrangements. In the cutting garden, pair with sunflowers, lilies, and roses for diverse, interesting bouquets.

Bells of Ireland performs best in moderately fertile, well-drained soil with a pH of 6.5-7.5. The plants prefer slightly alkaline conditions. Work compost into the planting area and apply a balanced slow-release fertilizer at transplanting time. Avoid heavy feeding, which produces lush growth prone to flopping. A single mid-season application of liquid fertilizer is sufficient for most situations.

Ideal Temperature

Hardiness Zone Compatibility

Cut Bells of Ireland when the bells along the stem are fully developed and a rich green color. Cut in the morning with long stems. Remove the leaves along the stem (they wilt quickly and detract from the display) and condition in deep, warm water for several hours before arranging. The stems last 7-10 days in fresh water and are a staple of floral design for their unique vertical line and green color.

Storage & Preservation

Bells of Ireland dries superbly and is one of the most popular dried flowers. Hang stems upside down in a dark, warm, well-ventilated area for 2-3 weeks. The bells dry to a lovely pale green or straw color and maintain their shape indefinitely. For preserved green color, use silica gel drying. The dried stems are stunning in autumn and winter arrangements. Save seed by allowing some stems to dry on the plant.

Troubleshooting Common Problems

Erratic germination is the biggest frustration—be patient and sow more seed than you think you need. Seeds that are not cold-stratified may fail entirely. Tall stems frequently need staking, especially in exposed or windy positions. The leaves along the stem are unremarkable and often removed for display, but leaving them on the plant is essential for photosynthesis and strong growth.

Growing Tips

1. Refrigerate seeds in a damp paper towel for 10 to 14 days before sowing to break dormancy and dramatically improve germination rates from roughly 30 percent to over 70 percent.
2. Surface sow seeds or cover them with only the thinnest dusting of vermiculite, as Bells of Ireland seeds require light exposure to trigger germination.
3. Direct sow outdoors in early spring as soon as the ground can be worked, since the seeds benefit from natural temperature fluctuations between cool nights and mild days.
4. Space plants 12 inches apart in rows 18 to 24 inches wide to allow adequate air circulation, which reduces susceptibility to powdery mildew and other fungal issues.
5. Install support stakes or a grow-through grid when plants reach 12 to 18 inches tall, as the heavy flower spikes can cause mature plants to topple in wind or rain.
6. Water at the base of the plants rather than overhead to keep the foliage dry and prevent leaf spot diseases common in the Lamiaceae family.
7. Pinch out the growing tip of young plants when they reach 8 to 10 inches tall to encourage branching and more flower spike production per plant.
8. Sow successive plantings every 3 to 4 weeks from early spring through late spring to ensure a continuous supply of fresh stems throughout the summer months.
9. Harvest stems for arrangements early in the morning when the plants are fully hydrated, cutting when at least half of the calyces on a spike are fully open.
10. Allow a few plants to go to seed at the end of the season, as Bells of Ireland self-sow reliably and volunteer seedlings will often appear the following spring with minimal effort.