How to Grow Ammi majus
(Bishop's Flower) from Seed
The finest white filler in the cutting garden — floating clouds of lace-cap blossom on tall strong stems, flowering all summer from a single sowing, and equally stunning in a border or a bouquet
There is a reason Ammi majus has become one of the most-grown cutting garden annuals in Britain over the past decade: there is simply nothing else that does what it does. Those floating, airy clouds of white lace-cap blossom — each flowerhead a perfectly formed flat-topped umbel of dozens of tiny white flowers on radiating stems, the whole thing as light and diffuse as sea-foam — have an ability to transform any arrangement or border planting they are placed into. They add airiness to heavy arrangements, structure to loose ones, and a romantic, naturalistic quality to both that no other flower quite replicates.
Ammi majus is Bishop's Flower — so called for the bishop's-lace quality of the intricate flowerheads. It is a hardy annual, related to cow parsley and Queen Anne's lace, that grows quickly to 90–120cm, flowers from midsummer right through to the first frosts if cut regularly, and self-seeds freely in sheltered gardens. An autumn sowing produces bigger, more floriferous plants that flower earlier the following year; a spring sowing provides a reliable summer display. Both approaches have genuine value, and many cutting gardeners grow two waves deliberately to extend the season.
Quick Facts at a Glance
Plant Type
Hardy Annual
Sowing Time
Sep–Oct (preferred) · Mar–May direct
Flowering Months
June – October
Position
Full sun to light shade
Height & Spread
90–120cm · 40cm
Difficulty Rating
2 out of 5 — Easy
Understanding the Plant
Ammi majus belongs to the Apiaceae family — the same family as cow parsley, fennel, dill and carrot — and it shares the characteristic flat-topped umbel flowerhead that makes all members of this family so visually distinctive. It originates from the Mediterranean and Middle East regions, where it grows in open, sunny, disturbed ground. It is a true hardy annual, completing its life cycle in a single season, though it self-seeds so reliably in the right conditions that it can appear perennial.
The flowerhead structure is what distinguishes Ammi majus from its relative Ammi visnaga. Where visnaga produces denser, more dome-shaped heads with a greener tinge — more architectural and structural — majus produces the loose, lacy, flat-topped heads that look almost like fine hand-made lace and catch light in a way that creates an impression of weightlessness. This quality makes it irreplaceable as a cut flower filler: it adds volume without adding visual weight, a combination that no other annual achieves quite as effectively.
Autumn Sowing — The Real Advantage
Sowing Ammi majus in September or October and allowing the seedlings to overwinter as small rosettes in a cold frame or sheltered spot consistently produces bigger, more vigorous plants with stronger stems that flower two to four weeks earlier than spring-sown plants. The cold stratification of winter appears to trigger a more robust root system, and the resulting plants are noticeably superior in stem length, flower size and overall performance. If you only sow once, sow in autumn.
⚠️ Skin Irritation — Handle with Care
Ammi majus belongs to a plant family that contains phototoxic compounds — chemicals that can cause skin irritation or blistering when the sap contacts skin and the skin is then exposed to sunlight. This is the same reaction caused by giant hogweed, though much milder in ammi. When cutting, handling or deadheading Ammi majus, particularly in sunny weather, it is advisable to wear gloves and long sleeves. Wash any sap from skin promptly and avoid sun exposure on affected areas. Most gardeners handle it without any problems, but sensitive individuals should take care.
When & How to Sow
The single most important thing to understand about sowing Ammi majus is that it develops a long taproot and strongly dislikes having that root disturbed at transplanting. Direct sowing into the position where plants are to flower is the preferred method and consistently produces the most confident-growing plants. When indoor sowing is preferred — for earlier flowers, or to avoid slug damage on seedlings — use deep individual modules or pots and handle the root ball with great care at planting out.
Two Sowing Options
Autumn direct (September–October) — recommended. Scatter seed thinly on a prepared seedbed at around 1cm depth. Seedlings overwinter as small rosettes and establish strongly, producing earlier, more vigorous plants the following summer. Spring direct (March–May). Equally viable — scatter on a prepared seedbed once the soil has reached around 12°C. Flowering from July onwards. Both work well; autumn plants are simply superior in performance.
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Prepare a fine seedbed in a sunny or lightly shaded position. Rake to a fine tilth, removing stones and large debris. Ammi grows well in reasonably fertile, well-drained soil. Avoid very rich, heavily manured ground which produces lush leafy growth and floppy stems.
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Scatter seed thinly and cover to approximately 1cm depth. Unlike many annuals, Ammi majus seed does not need to be surface-sown — a light covering is correct. Rake in gently or cover with a fine scattering of sieved compost. Water gently with a fine rose.
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Thin to 20–30cm apart once seedlings are established. Ammi grows large — overcrowded plants produce weaker, leggier stems. Thin promptly and use the thinnings elsewhere or as cut seedlings. The remaining plants will establish into strong, well-rooted specimens.
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For indoor sowing, use deep individual modules. Sow one to two seeds per module at 1cm depth. Pot on into deep 9cm pots when roots emerge from the module base — do not allow plants to become rootbound. Harden off carefully and transplant with the entire root ball intact, disturbing the roots as little as possible. Handle carefully: a broken taproot at transplanting permanently stunts the plant.
Growing On Tips
Sun & Shade
Full sun produces the strongest, most upright stems and most abundant flowering. Ammi tolerates light partial shade — up to around four hours of direct sun per day — without significant loss of performance. In heavy shade, stems become leggy and the plant is prone to flopping. In a partly shaded cottage garden border it still performs admirably well.
Staking
At 90–120cm, Ammi majus benefits from support in exposed positions or windy gardens. Place twiggy pea-sticks or grow-through supports in early spring before stems reach 30cm. In sheltered gardens or when plants have been autumn-sown into their final position, they are often self-supporting. Strong, healthy plants with thick taproots rarely need staking.
Cut-and-Come-Again
Ammi majus is a genuine cut-and-come-again plant — each stem cut back to a visible side shoot triggers the production of new flowering side shoots from that point. Regular cutting for the vase is therefore not just rewarding but actively beneficial for the plant, extending the flowering season significantly beyond what an uncut plant would produce. Cut early and cut often.
Self-Seeding
Ammi majus self-seeds prolifically in sheltered gardens with bare or lightly disturbed soil. Allow some plants to go fully to seed in autumn, then disturb the soil surface lightly around them to create suitable germination conditions. Seedlings that overwinter are often stronger than fresh-sown ones. In small gardens, be prepared to manage self-seeding by removing unwanted plants early.
Feeding
Average, reasonably fertile soil provides all the nutrition Ammi needs. Avoid very high nitrogen feeds which produce leafy growth and weak, hollow stems at the expense of flowers. A light balanced feed at planting out and once again in midsummer is ample. In very poor, sandy soils, a little more feeding produces noticeably stronger results.
Slug Protection
Young Ammi seedlings — particularly when sown direct in autumn — are vulnerable to slug and snail damage. Protect autumn-sown seedlings with organic slug pellets or copper tape until they reach 10cm in height, at which point they become less palatable and more able to withstand light grazing. Spring-sown direct plants grow quickly and are similarly vulnerable only in the seedling stage.
Common Problems & How to Fix Them
| Problem | Likely Cause | What to Do |
|---|---|---|
| Slow or patchy germination | Cold soil or old seed | Ammi majus germinates across a wide temperature range (12–24°C) but is slower in cold conditions. Be patient in early spring — germination that appears to have failed may simply be waiting for the soil to warm. Seed needs to be reasonably fresh; germination rates decline noticeably in seed that is more than a year old. |
| Transplants fail or stunt | Taproot damaged at transplanting | This is the most common cause of transplant failure. Use deep modules, transplant as early as possible before roots become long, handle the root ball as a complete unit without breaking or disturbing it, and water in well. Plants set back by taproot damage may recover slowly or not at all. |
| Stems flopping or falling over | Insufficient support, rich soil, wind damage | Install support before stems reach 30cm. Avoid very rich, fertile soil. In windy positions, place supports early. Autumn-sown plants with deep, established taproots are significantly more self-supporting than late spring-sown ones. |
| Skin irritation after handling | Phototoxic sap + sunlight | Wear gloves when handling the plant in sunny conditions. Wash any sap from exposed skin promptly. Avoid sun exposure on recently sap-contacted areas for several hours. Most people are not noticeably sensitive, but in bright summer sun caution is worthwhile. |
| Short flowering season | Plants not cut regularly | Ammi left without cutting reaches its natural seed-setting phase quickly and stops producing new flowers. Regular cutting — for the vase or as deadheading — is the key to a long season. Cut back to visible side shoots rather than removing whole stems. |
| Plants become invasive through self-seeding | Prolific seed production | Deadhead any plants not wanted for self-seeding before seed is fully ripe. Remove unwanted seedlings when small — they are easy to pull at the seedling stage. Once established with a taproot, larger plants are harder to remove. |
When to Expect Flowers
Autumn-sown Ammi majus typically comes into flower in June — sometimes late May in mild seasons — producing its peak display in June and July before continuing through to September or October with regular cutting. Spring-sown plants flower from July, typically peaking in August, and continue until the first frosts. Running both sowings produces a continuous supply of stems from June through to October.
In the cutting garden, many growers make a second spring sowing in May specifically to extend the season into September and October when the first sowing has declined. This successive sowing approach is one of the simplest ways to ensure a continuous supply of stems across the whole summer.
Sow direct in autumn for the strongest plants and earliest blooms, or in spring for a reliable summer display — or sow both waves for flowers from June to October.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
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| 🍂 Autumn Sow |
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| 🌿 Spring Sow |
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| 🤍 Flowering |
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Cutting & Arranging
Ammi majus is one of the most important and most versatile cut flowers you can grow, filling a role in arrangements that no other summer annual quite replicates. Florists have used it extensively for decades precisely because of what it brings to a mixed bouquet — the quality of adding airiness, light and naturalistic structure without dominating or competing with the focal flowers.
Harvesting for the Vase
Cut when flowerheads are approximately three-quarters open — the individual florets clearly visible and spread, but before the whole head becomes loose and fully mature. Cut early in the morning with long stems, ideally wearing gloves in sunny conditions. Plunge immediately into deep cool water and condition in a dark, cool place for several hours before arranging. Vase life is typically seven to ten days — excellent for a lace-type flower.
The Art of Ammi Arrangements
The key to using Ammi effectively is restraint — it is the supporting player, not the lead. Two or three stems of Ammi in a mixed summer bouquet adds more than twice the visual impact you might expect, because the airy structure creates visual space and movement that makes every other flower in the arrangement look better. It works particularly beautifully with bold, structural flowers (dahlias, sunflowers, roses) and with delicate, fine-stemmed flowers (sweet peas, cosmos, nigella) — softening the former and supporting the latter.
Plant Specifications
The white filler that makes every bouquet better
Once you have grown Ammi majus and discovered what a few stems can do to a mixed summer arrangement — the lightness, the naturalistic structure, the way it makes roses look more romantic and cosmos look more abundant — it becomes an annual non-negotiable in the cutting garden. Grow it from an autumn direct sowing for the strongest plants and earliest flowers, cut it regularly from June onwards, and let it self-seed where conditions suit for an ever-growing supply. Our Ammi majus seeds are selected for vigour and reliable germination — sow them this September and let the lace begin.
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