How to Grow Antirrhinum
'Sweet Duet Apple Blossom' from Seed
Fully double, ruffled azalea-type flowers in the softest porcelain pink and cream — lightly scented, exceptionally long-lasting in the vase, and as beautiful in a wedding bouquet as in a cottage garden border
The Sweet Duet series takes everything that makes antirrhinum appealing — the cottage garden romance, the long summer season, the ease of growing — and delivers it in an entirely different and entirely captivating flower form. Instead of the traditional closed mouth of a classic snapdragon, each bloom opens fully to reveal a completely double flower composed of layer upon layer of soft, ruffled petals — more like a miniature rose or a very full azalea than anything conventionally snapdragon-like. In the Apple Blossom colour, the flowers are a soft, porcelain bicolour of pale pink and cream-white, the combination so delicate and so romantic that it has made this variety a genuine favourite for wedding floristry and for cottage garden lovers who want something that photographs like a dream.
The open-faced flower structure has an interesting practical consequence: because the flowers are not closed and are therefore harder for bees to pollinate, they remain unpollinated for longer. Unpollinated flowers receive continuous hormonal signals from the plant to keep producing — so they last on the stem for ten days or more, significantly longer than traditional single-flowered varieties. The scent adds another dimension entirely: Sweet Duet Apple Blossom is one of the few antirrhinum varieties with a genuinely noticeable sweet fragrance, which is most intense on warm, still afternoons and which transforms the experience of cutting these flowers for the house.
Quick Facts at a Glance
Plant Type
Half-Hardy Annual (F1)
Sowing Time
Jan–Mar indoors · Aug–Sep overwinter
Flowering Months
June – October
Position
Full sun
Height & Spread
45–55cm · 30cm
Difficulty Rating
3 out of 5 — Moderate
Understanding the Plant
The 'Sweet Duet' series represents a distinct direction in antirrhinum breeding — the azalea-flowered type, where the traditional closed two-lipped flower is replaced by a fully open rosette of multiple petals. This flower form is genetically distinct from both the traditional snap type and the open-faced but single-flowered types, and it produces a flower that reads as genuinely different in a border or arrangement — more rose-like, more opulent, more aligned with contemporary romantic aesthetics than the conventional snapdragon.
As an F1 hybrid, Sweet Duet Apple Blossom produces consistent plants with uniform height, flower size and colour — every plant in a batch performs identically. The hybrid vigour inherent in F1 breeding also contributes to the strong, well-branched habit and the improved disease resistance that makes this variety particularly reliable through the long summer season. Seed cannot be saved and replanted true-to-type from F1 plants — fresh seed produces the best results each season.
Why the Scent Matters
Sweet Duet Apple Blossom is one of very few antirrhinum varieties with genuinely noticeable fragrance — a sweet, clean scent that is most apparent on warm, calm afternoons and that fills a room when the flowers are brought indoors. The scent comes from volatile compounds in the petals and is strongest in flowers that have just opened rather than in older blooms. Cutting stems in the morning when flowers are fresh and placing them in a cool room preserves the fragrance best.
The Longer Vase Life — Why It Happens
The open-faced double flower structure means bees cannot easily access or pollinate the blooms. Unpollinated flowers continue receiving hormonal signals from the plant that essentially tell them to keep going — so they remain in perfect condition for ten days or more rather than the seven to eight days typical of single-flowered varieties. This is not a deliberate breeding decision but a fortunate consequence of the flower structure, and it makes Sweet Duet Apple Blossom particularly valuable as a cut flower where longevity in the vase matters.
When & How to Sow
Sweet Duet Apple Blossom follows the same sowing requirements as all antirrhinum: surface sow with light access at consistent warmth. The Sweet Duet series benefits from slightly warmer conditions than some varieties — 20–24°C produces the most reliable germination. Sow from January to March for summer flowers, or in August or September for overwintering in a cold frame for an earlier, stronger display the following spring.
Pinch at 15cm for Sweet Duet
The pinching technique for Sweet Duet is the same as for other antirrhinum but the recommended height is slightly taller — 15cm rather than 10cm. This reflects the somewhat different branching architecture of the azalea-flowered type. Wait until seedlings reach 15cm before pinching, and the resulting lateral shoots will produce strong, well-spaced flowering stems rather than congested ones.
-
Surface sow in pots or modules at 20–24°C. Do not cover — antirrhinum seed requires light to germinate. Press gently onto moist seed compost. A heated propagator at the higher end of the temperature range produces faster, more uniform germination than a windowsill in January or February.
-
Germination in 10–21 days. Can be somewhat slower than standard snap types — be patient. Keep compost consistently moist and warm throughout. Move to maximum light as soon as seedlings appear.
-
Grow on in good light at 15–18°C. Cooler conditions after germination produce more compact, sturdy plants. Avoid warm, dim environments which produce drawn, weak seedlings.
-
Pinch at 15cm. Remove the growing tip cleanly between finger and thumb. The plant will produce four to six lateral shoots from the nodes below the pinch, each of which develops into a flowering stem. The delay is ten to fourteen days; the gain in total stem count is substantial.
-
Plant out from late May to June. Sweet Duet Apple Blossom is somewhat more temperature-sensitive than traditional snap types — wait until genuinely warm, settled weather before planting out. Space 30cm apart in full sun and well-drained soil.
Growing On Tips
Full Sun is Essential
Full sun develops the softest, most romantic colour tones — the porcelain pink appears almost translucent in strong summer light, which is one of the most beautiful qualities of this variety. In shade the colour becomes duller and the stems weaker. Minimum six hours of direct sun produces the finest results.
Cutting & Deadheading
Cut or deadhead spent flower spikes promptly to encourage continuous production. For the vase, cut when the lowest flowers on the spike are fully open but before the uppermost buds open. Sweet Duet's longer individual flower life means the overall stem remains attractive for longer — allow it to develop before cutting rather than rushing to cut early.
Keep Cut Stems Vertical
As with all antirrhinum, the stems are geotropic — they bend permanently upward if laid horizontal after cutting. Always place cut stems immediately into a bucket of water upright. Transport them upright. Condition them upright in a cool, dark place before arranging. Horizontal stems develop permanent curves within an hour in warm conditions.
Feeding
A balanced liquid fertiliser fortnightly from planting out sustains the long season. High-potash feeding from July onwards encourages continued flower production over leafy growth. Sweet Duet Apple Blossom is a vigorous F1 variety and responds well to regular feeding with clearly improved stem length and flower count compared with unfed plants.
Rust Resistance
As an F1 hybrid, Sweet Duet has improved resistance to snapdragon rust compared with older open-pollinated varieties. Remove any orange-spotted leaves promptly. Ensure 30cm plant spacing for adequate airflow. Avoid overhead watering. In practice, the disease resistance is robust enough that most gardeners experience little to no rust through a normal UK summer.
The Wedding Flower
Sweet Duet Apple Blossom is genuinely one of the finest home-grown wedding flowers available from seed. The delicate porcelain bicolour, the ruffled double petals, the scent and the ten-plus-day vase life all make it ideal for bridal arrangements. Grow at succession intervals for consistent supply during summer wedding seasons — a single sowing in February and a second in April provides flowers from June through to September.
Common Problems & How to Fix Them
| Problem | Likely Cause | What to Do |
|---|---|---|
| No germination | Seed covered or insufficient warmth | Surface sow without covering at 20–24°C. A heated propagator is strongly recommended for January sowings. Sweet Duet can be slower to germinate than standard snap types — allow up to 21 days before assuming failure. |
| Flowers not fully double | Stress or cool growing conditions | Plants under stress — cold, drought, root restriction — may produce semi-double or single flowers. Ensure warm growing conditions, adequate feeding, no rootbounding, and full sun. F1 varieties produce very consistent results in ideal conditions. |
| Curved stems after cutting | Geotropic response — stems laid horizontal | Always keep cut stems vertical in water from the moment of cutting. Never lay them horizontally. Stems develop a permanent upward curve within an hour of being placed horizontal — this cannot be reversed. A tall bucket of water is the essential transport vessel for all antirrhinum. |
| No scent | Flowers too old, cold weather, or plant stress | The scent is most pronounced in freshly opened flowers in warm, calm conditions. Cut early in the morning when scent compounds are freshest. Cool or wet weather significantly reduces fragrance intensity. Stressed plants also produce less scent — well-fed, well-watered plants in full sun are the most fragrant. |
| Short flowering season | Insufficient deadheading | Deadhead or cut regularly — Sweet Duet produces new stems in response to cutting but declines quickly if allowed to set seed. The longer individual flower life can create the impression that the plant is still productive when it has actually stopped producing new stems. Check regularly for new bud formation rather than relying on the appearance of existing flowers. |
When to Expect Flowers
Sweet Duet Apple Blossom takes approximately 14–16 weeks from sowing to first flower. A January sowing flowers from May or June; February from June or July. An August or September sowing overwintered in a cold frame produces flowers from April or May the following year — the finest plants with the longest, strongest cutting stems. With regular cutting, the season runs until the first hard frosts of October.
Sow indoors from January for summer flowers, or in August for overwintering — the ruffled double blooms appear from June and continue until the first frosts, with each flower lasting ten days or more in the vase.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 🌱 Sow Indoors |
|
|
|
|
|
|||||||
| 🪴 Plant Out |
|
|
||||||||||
| 🌸 Flowering |
|
|
|
|
|
Plant Specifications
The snapdragon that looks like a rose and lasts like a florist's dream
Antirrhinum 'Sweet Duet Apple Blossom' is the snapdragon for anyone who has ever looked at a traditional snap-mouthed antirrhinum and wished it were just a little more opulent, a little more romantic, a little more like the flowers in a Chelsea show garden. The fully double ruffled flowers, the soft porcelain bicolour, the sweet scent on warm afternoons, the ten-day vase life — all of these make this a genuinely exceptional growing experience from a seed packet. Sow in January, pinch at 15cm, keep stems upright, and let the romance begin.
Shop Sweet Duet Apple Blossom Seeds →