How to Grow
Scabious 'Black Knight' from Seed
The near-black velvet pincushion -- Hardy Annual H4 producing deep maroon-purple almost-black dome flowers with contrasting white-tipped stamens on 90cm stems; subtle honey fragrance; RHS Plants for Pollinators; cut-and-come-again (the more you cut the more it produces); support 90cm stems with twiggy pea sticks early; surface press/fine vermiculite/light; 18-20°C; 10-14 days; March-April or September to overwinter; full sun; neutral to alkaline well-drained soil; known as Blackamoor's Beauty and Mournful Widow since the early 1600s
Scabious 'Black Knight' (Scabiosa atropurpurea) is the most dramatic flower in the Bishy Scabious range: the deep maroon-purple that so closely resembles black velvet that it is frequently mistaken for the much-sought-after black flower that gardeners have been pursuing in vain across the plant kingdom for centuries. The flowers are not technically black -- in strong direct sunlight, the deep maroon character becomes visible -- but in the dappled light of a summer border, the shade of a vase arrangement, or the warm interior light of a house, they read as very close to black, and the effect is of a small, beautifully-formed velvet globe that belongs in a different category from the cheerful open faces of most summer annuals.
The white-tipped stamens that project from the centre of each flower head provide the specific aesthetic detail that earns the "pincushion" name most completely in this variety: against the near-black of the petals, the dozens of tiny white-tipped pins that project from the dome are visible individually, creating the impression of a pincushion that has been threaded with white-headed pins -- a botanical craft object that sits at the intersection of the natural and the artificially designed. On warm days, the flowers release a subtle, sweet honey fragrance that makes Black Knight additionally seductive -- a near-black flower that smells of summer honey is a combination that no other garden annual provides.
Quick Facts at a Glance
Plant Type
Hardy Annual H4 -- deep maroon/near-black pincushion; the drama plant; RHS Pollinators
Flowers
Deep maroon-black velvet pincushion with contrasting white-tipped stamens; 90cm; honey scent
Cut-and-come-again
The more you cut, the more it produces -- the florist pick-and-repeat plant
History
Known as Blackamoor's Beauty and Mournful Widow since the early 1600s
Support
90cm wiry stems need early twiggy stick support to prevent summer storm flopping
Difficulty
2 out of 5 -- support and consistent deadheading are the two things to master
Understanding the Mournful Widow
Light Required -- Surface Press or Very Light Vermiculite Dusting
Scabiosa seeds need light to germinate. Sow onto moist compost and press gently, covering with only the finest dusting of vermiculite. Do not bury. Alternatively press seeds gently onto the compost surface without any covering at all.
Free-Draining Soil -- Neutral to Alkaline -- Full Sun
All annual Scabiosa thrive in neutral to slightly alkaline (chalky) soil in full sun with excellent drainage. They are tolerant of poor soil but suffer in waterlogged or heavy, wet clay through the winter. Add horticultural grit to clay planting holes.
Support the Tall Wiry Stems Early in the Season
The 90cm wiry stems of Scabiosa atropurpurea need support from twiggy pea sticks or netting placed when plants are 20-30cm tall. Once supported, the stems grow up through the structure and maintain themselves through rain and wind. Without support, the stems flop dramatically after the first summer storm.
History -- Blackamoor's Beauty and Mournful Widow
Black Knight has been grown in British gardens since at least the early 17th century, when it appeared under the descriptive names "Blackamoor's Beauty" and "Mournful Widow" -- the latter reflecting the association between the very dark flower colour and mourning dress. The name "Blackamoor's Beauty" reflects both the colour and the admiration the flower provoked: it was a plant valued precisely for its unusual, near-black colouring at a time when most garden flowers occupied the warm range of pinks, reds, and yellows. The name Scabiosa itself derives from the Latin for "scabies" -- the plant was believed in medieval times to cure scabies and other skin conditions, with Nicholas Culpeper (17th century) prescribing it for wounds, swollen throats, snake-bite, and plague.
Sowing & Growing On
Sow Indoors Mar-Apr (or Sep to Overwinter for Strongest Plants); Light Press + Fine Vermiculite; 18-20°C; 10-14 Days -- Support Early -- Cut-and-Come-Again for Extended Season
Sow indoors March-April at 18-20°C with a fine vermiculite dusting (light required; 10-14 days). Alternatively sow in September and overwinter for the earliest, strongest plants. Plant out late May in full sun with excellent drainage. Insert support at 20-30cm. Deadhead consistently -- the more you cut, the more it produces.
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Sow March-April at 18-20°C with fine vermiculite dusting, or September for overwintered stronger plants. Light required -- surface press with fine vermiculite only. Germination 10-14 days at 18-20°C. The September option (sow, cover with fleece or move to a cold frame, allow to overwinter as small rosettes, plant out in March) produces significantly larger, earlier-flowering plants that begin their display in June rather than July.
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Insert twiggy support at 20-30cm plant height -- before the stems need it. Black Knight grows 90cm tall on wiry, branching stems that look self-supporting until the first significant summer rain or wind event, at which point they collapse completely. Twiggy pea sticks inserted around the plant at 20-30cm height, with additional canes at 50-60cm for particularly exposed positions, prevent this. Stakes inserted after flopping rarely restore the stem to a satisfactory upright position.
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Cut consistently for the vase -- cut-and-come-again produces more flowers per cutting. The more you pick, the more it produces! This is accurate -- each stem cut for the vase triggers the plant to produce 2-3 lateral buds below the cut that each develop into new flowering stems. Leaving flowers on the plant to set seed redirects energy into seed production and reduces subsequent flowering. Regular cutting for the vase is both the most effective deadheading and the most rewarding harvest from this plant.
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Cut for the vase when flowers are freshly open. Vase life 7-10 days. Cut when the central dome is well-formed and the outer florets are freshly open -- before the centre stamens begin to elongate significantly. Re-cut at an angle under water and condition in deep water for 4 hours. The honey fragrance is particularly noticeable when the stems are first brought indoors.
Growing On & Care
The Near-Black in the Border
Black Knight is a specific and valuable design tool: very dark flowers against the typical summer palette of pinks, whites, lavenders, and warm oranges create a visual anchor that "grounds" the surrounding colours and prevents them from competing with each other. A group of Black Knight in a border full of pastel colours creates the punctuation -- the darkest note around which lighter notes organise -- that gives a soft-coloured border definition and depth. Against white companions (Ammi majus, white Cosmos), the near-black reads with maximum impact; against warm companions (Rudbeckia, Helenium), the dark maroon echoes and deepens the warm palette.
The Butterfly Landing Platform
The RHS Plants for Pollinators designation for Black Knight reflects the specific value of the pincushion flower form for butterflies: the flat, dome-shaped flower head provides a stable, well-defined landing platform from which the butterfly can probe for nectar without the instability of pendulous or complex-structured flowers. On warm summer days, Red Admirals, Peacocks, Tortoiseshells, and Gatekeepers use Black Knight as a regular feeding station, remaining on individual flower heads for minutes at a time before moving to the next. The honey fragrance released by the flowers on warm afternoons appears to contribute to the attractiveness of the plant to both butterflies and honeybees.
The Florist Perspective
Black Knight holds a specific place in the cut flower world as the dark, moody element that provides depth in a mixed summer bouquet: the near-black velvet domes alongside the bright pincushions of the Imperial Mix; the deep maroon echoing a similarly-coloured rose or Dahlia; or the dramatic contrast with pale flowers (white sweet peas, cream Cosmos) where the dark-and-light combination is the entire compositional point. A firm favourite for florists because it adds a moody, sophisticated touch to any summer bouquet -- and this is borne out by its consistent presence in contemporary wedding and event floristry where the dark, velvety dome provides the statement element.
Succession Sowing for a Long Display
Individual Black Knight plants provide their main display for 8-10 weeks from first flower. Succession sowing every 3 weeks from March through May -- or a combination of spring sowing and September overwintering -- extends the Black Knight display from June through October, ensuring a continuous supply of dark pincushion flowers for the vase and the border throughout the summer season. The September overwinter sowing produces June-August flowers; a March indoor sowing produces July-September flowers; an April-May sowing produces August-October flowers. Three-sowing succession provides near-continuous Black Knight availability from June to October.
Neutral to Alkaline Soil -- The Chalk Preference
Scabiosa atropurpurea in general and Black Knight specifically perform most generously in neutral to slightly alkaline (chalky) soil. In acidic soil (pH below 6.5), growth is satisfactory but the display is less generous and stem quality reduced. In chalky or limestone-based soil at pH 7.0-7.5, Black Knight grows most vigorously and produces the largest, most richly-coloured flower heads. In acid gardens, a top-dressing of garden lime (applied in autumn at the manufacturer's recommended rate) raises pH slightly over two or three seasons and progressively improves the performance.
Heat Tolerance -- The Late-Summer Virtue
One of Black Knight's most practically valuable qualities is its continued performance through the hottest periods of the UK summer. While many mid-summer annuals slow their flowering in July-August heat, Scabiosa continues producing its dark pincushions through warm periods provided the soil retains adequate moisture. Consistent watering in dry spells (not overhead watering, which promotes mildew -- water at the base) and a mulch around the plants to retain soil moisture allows Black Knight to maintain its cut-and-come-again production through the warmest weeks, when the dark dramatic flowers are most needed in the summer vase.
Sowing & Flowering Calendar
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
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| September sow (overwinter for earliest strongest plants) |
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| Spring sow (Mar-Apr indoor) |
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| Plant out (late May) |
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| From Sep sow: flowers Jun-Aug |
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| From Mar-Apr sow: flowers Jul-Oct |
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Common Problems & Solutions
| Problem | Likely Cause | What to Do |
|---|---|---|
| Stems flopping after summer rain | No support installed before flopping occurred | Insert twiggy pea sticks at 20-30cm plant height -- before the stems need them. Flopped stems rarely fully recover. In future, support every plant immediately after planting out. |
| Display ending early; few flowers by August | Not cut consistently; seeds setting | Cut every flower stem for the vase or deadhead as soon as it opens. The cut-and-come-again mechanism only works with consistent cutting. Leaving even some flowers to set seed redirects energy and reduces subsequent flowering. |
| Pale, washed-out colour; not deep maroon | Acidic soil; poor drainage; insufficient sun | Scabiosa performs at its darkest in neutral to alkaline soil with excellent drainage in full sun. Acidic soil, waterlogging, or shade all reduce colour saturation and plant vigour. |
| Poor germination | Temperature below 18°C; seeds buried | Surface press with fine vermiculite only. Maintain 18-20°C consistently. Below 18°C, germination is significantly reduced. |
Plant Specifications
The near-black velvet that smells of honey -- cut every stem and it grows two more; the more you pick the better it gets
Sow March-April at 18-20°C (fine vermiculite; light; 10-14 days) or September to overwinter for earliest plants. Plant late May in full sun with excellent drainage. Insert twiggy support at 20-30cm height immediately. Cut every flower stem consistently for the vase -- the cut-and-come-again mechanism produces more flowers with every picking. The honey-scented near-black velvet domes continue from June through October.
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