Callistephus chinensis 'Peony Mix' is a Half-Hardy Annual (H2) and holder of the RHS Plants for Pollinators designation — the peony-flowered China aster in a purple-to-white cool palette, producing fully double, incurved flower heads of 8–10cm diameter on 60cm stems from August to October.

The Four-Aster Comparison: To choose clearly across the range's four China asters — 'Duchess Mixed' (July–October, 12 colours including blues, fragrant, peony form, 70cm, 100 seeds, RHS Pollinators) is the broadest and earliest peony aster; 'Giants of California' (August–October, 5 refined colours, 12cm heads, professional Californian breeding, 100 seeds, Fleuroselect Quality) is the large-headed ostrich plume; 'Ostrich Plume' (August–October, 5 soft cottage colours, heirloom, twisted petals, 45–60cm, 200 seeds, Fleuroselect Quality) is the compact heirloom ostrich plume; 'Peony Mix' (August–October, 4 cool purple-pink colours, 8–10cm heads, 60cm, 100 seeds, RHS Pollinators) is the cooler, more restrained peony form for the gardener who wants the incurved pom-pom head in a coherent purple-lavender-pink-white palette without the full rainbow of Duchess Mixed.

The Purple-Dominant Palette: The specific colour register of Peony Mix — deep purple, vibrant pink, soft lavender, white — is the cool end of the aster spectrum, without the warm tones (yellow, coral, apricot, scarlet) that appear in Duchess Mixed's twelve colours and without the crimson-to-rose register of the ostrich-plume varieties. This cool-dominant palette coordinates particularly well with the deep violet zinnias, the wine-dark cosmos, and the silver-blue and lavender combinations of the late summer border, providing the purple anchor around which other late-season flowers can be arranged both in the garden and in the vase.

8–10cm Heads — the Substantial Focal Flower: The stated 8–10cm head size puts Peony Mix firmly in focal flower territory — large enough to be the dominant flower in a mixed arrangement rather than a supporting or filler role, but not as imposing as the Giants of California's 12cm heads. In practical terms this means a vase of five Peony Mix stems alongside a few ammi or cosmos stems produces a complete, well-proportioned arrangement without any additional focal flower; the aster heads are present enough to carry the arrangement without overwhelming it.

'Peony Mix' is grown in exactly the same way as 'Duchess Mixed' — same sowing timing, same germination temperature, same planting distances, same support requirement, same cut-at-full-development rule. The practical difference is the crop rotation, which applies equally to all four asters.

How to Sow:
Sow indoors from March to April. Sow onto moist seed compost and cover with a fine 3–5mm layer of vermiculite. Maintain a temperature of 18–21°C. Germination is reliable and typically occurs within 10–21 days.

Planting Out:
Plant out from late May to June after thorough hardening off. Space plants 30cm apart in full sun and rich, well-drained soil enriched with organic matter. Avoid any position where China asters have grown in the previous two to three years. In exposed positions, install horizontal support netting at 30–40cm height when plants reach 20cm — the 8–10cm heads are substantial and benefit from support in wind.

Feeding:
A weekly balanced liquid feed once plants are established and showing flower buds improves head size and the number of secondary stems. China asters are productive, high-nutrient plants and respond well to regular feeding, unlike some of the leaner-soil annuals in the range.

Cutting:
Cut when the flower head is three-quarters to fully open — China asters do not continue to open significantly in the vase and a stem cut too tight may not open fully indoors. Snip at a 45-degree angle for maximum water uptake. Remove all leaves below the waterline, change water every two to three days, and keep in a cool room for vase life of up to ten days.

The cool purple-pink-lavender palette of 'Peony Mix' is one of the most naturally harmonious and most versatile late-summer colour registers — these companions create the most beautiful combinations:

• 🌻 Zinnia 'Giants of California': The Warm-Cool Contrast. The vivid coral, orange, scarlet, and hot-pink zinnias alongside the deep purple, vibrant pink, and lavender of 'Peony Mix' creates the most energetic warm-cool contrast available from the late-summer cutting garden — the warm, saturated zinnia tones making the cool aster purples appear richer and deeper, and the cool aster tones making the warm zinnias appear more vivid. Both flower simultaneously in August and September, both produce multiple cutting stems per plant, and both have long vase lives that make them genuinely practical together. In a large vase, orange zinnia heads alongside deep purple aster pom-poms is one of the most striking and most colour-theoretically pure combinations in the entire annual range.
• 🌿 Ammi Majus: The White Lace Separator. The pure white lace umbels of Ammi Majus — if sown in autumn for the earliest possible plants — overlap with the August beginning of the Peony Mix season and provide the finest and most classic white framework for the cool purple and pink aster heads. The white creates the visual space and separation between the more substantial aster pom-poms that prevents the arrangement from feeling crowded, while the intricate lace structure of the ammi umbel contrasts maximally with the dense, compact, fully-incurved structure of the peony aster. In a vase, deep purple Peony Mix heads alongside white ammi is an arrangement of considerable elegance and considerable restraint — cool, clean, and beautiful in a way that warm-coloured arrangements cannot quite achieve.
• 🌼 Rudbeckia 'Marmalade': The Harvest Gold Anchor. The warm, clear, uncomplicated golden-yellow of Rudbeckia 'Marmalade' daisy heads provides the warm anchor that the cool purple palette of 'Peony Mix' benefits most from — yellow and purple are complementary colours, and the golden rudbeckia intensifies the purple aster tones in the same way that gold intensifies violet in a stained glass window. The combination of the rudbeckia's open, flat, simple daisy face and the aster's dense, rounded, fully-incurved pom-pom creates a form contrast as well as a colour contrast, and the two together in a border or a vase capture the essence of the September garden more precisely than almost any other combination in the late-season range.
• 🌸 China Aster 'Duchess Mixed': The Complete Peony Collection. Growing 'Peony Mix' alongside 'Duchess Mixed' provides the most comprehensive peony-form China aster cutting garden available from the range — Duchess beginning in July with twelve colours including the blues and yellows that Peony Mix does not carry, Peony Mix arriving in August with a more unified cool purple palette that extends and complements the Duchess range. The two together cover seven months of peony-form aster from July to October with seventeen colours between them, and the tonally distinct cool-purple register of Peony Mix alongside the broader Duchess rainbow creates exactly the kind of variety within a single flower form that makes a cutting garden genuinely interesting to work with across the full season.

Sow indoors in March or April — 'Peony Mix' begins flowering in August, a month after 'Duchess Mixed', and continues through September and October, providing the most focused and most tonally cohesive purple-dominant display of all four China asters in the range during the peak months of the autumn cutting garden season.