Callistephus chinensis Optimo Red | China Aster Seeds
Callistephus chinensis Optimo Red is a professional spray-type China Aster developed for high-quality cut flower production, producing an abundance of large, chrysanthemum-shaped flowers in a rich, vibrant red. The Optimo series combines impressive flower size with strong stems, reduced basal branching and prolific flowering concentrated toward the upper part of the plant, creating highly usable stems for bouquets and professional floristry.
Optimo is particularly valuable for commercial production thanks to its strong resistance to Fusarium and lower susceptibility to Botrytis. The series was bred for high-density planting, allowing growers to produce attractive, uniform stems efficiently.
Plants reach approximately 60–75 cm, with large flowers measuring around 6–9 cm across. The intense red colour and distinctive chrysanthemum-like flower form make Optimo Red an excellent focal or supporting flower for summer and autumn arrangements.
Plant Information
Botanical name: Callistephus chinensis
Common name: China Aster
Series: Optimo
Variety: Red
Family: Asteraceae
Life cycle: Annual
Plant type: Spray-type cut flower
Plant height: 60–75 cm
Flower colour: Red
Flower size: approx. 6–9 cm
Flower form: Large, chrysanthemum-shaped
Use: Professional cut flower production
Germination: approx. 5–8 days
Germination temperature: 18–20°C
Plug production: approx. 4–5 weeks
Time to flower: approx. 18–21 weeks from sowing
Transplant to flower: approx. 14–16 weeks
Recommended spacing: approx. 10 × 10 cm
Rich Red Chrysanthemum-Shaped Flowers
Optimo Red stands out for its large, intensely red flowers with a distinctive chrysanthemum-like form.
The densely arranged petals give the blooms a full, substantial appearance that works beautifully in both mixed bouquets and more structured floral designs.
Unlike asters that produce heavy branching from the base, Optimo has reduced basal branching and abundant flowering toward the top of the plant. This creates attractive spray-type stems carrying several prominent flowers and makes harvesting particularly practical for cut flower production.
Optimo – Professional Cut Flower Series
The Optimo series was bred specifically for growers looking for a combination of flower quality, productivity and improved disease resilience.
Its key characteristics include:
Large 6–9 cm flowers • Chrysanthemum-shaped blooms • Spray-type growth • 60–75 cm stems • Reduced basal branching • Abundant top flowering • Suitable for dense planting • Strong against Fusarium • Lower susceptibility to Botrytis
Optimo Red is intended primarily as a professional cut flower, rather than as a compact bedding aster.
Improved Disease Resistance
One of the most important characteristics of the Optimo series is its strong resistance to Fusarium.
This is particularly valuable in China Aster production, where soil-borne disease can significantly affect plant quality and crop success.
Optimo is also described as being less susceptible to Botrytis, helping improve reliability and flower quality under suitable production conditions.
Good crop hygiene and rotation remain important. Where asters are grown repeatedly, rotating the production area can help reduce disease pressure and maintain healthier soil.
Sowing
For plug production, sow into 200–288-cell trays filled with a fine, well-drained seed-starting substrate.
Germination temperature: 18–20°C
Emergence: approximately 5–8 days
Recommended substrate pH during plug production: 5.5–5.8
Plug production time: approximately 4–5 weeks
Maintain consistent moisture during germination. Avoid both excessive moisture and allowing the substrate to become too dry, as either condition can reduce germination quality.
After germination, provide good light and air circulation to encourage compact, healthy seedlings.
Transplanting and Spacing
Transplant after approximately 4–5 weeks, once seedlings are well established.
For professional cut flower production, the recommended spacing is approximately:
10 × 10 cm
Optimo was bred for high-density production, and relatively close spacing encourages the development of useful cut-flower stems.
For the finishing crop, a soil or substrate pH of approximately 6.0–7.0 is recommended.
Growing Temperature
Recommended production temperatures are approximately:
Day: 16–25°C
Night: 13–16°C
The supplier specifically recommends maintaining night temperatures around 16°C or above when possible to help reduce the risk of malformed flowers.
Provide good ventilation and avoid prolonged excessive humidity, particularly because Botrytis and other fungal diseases can become problematic under humid conditions.
Day Length and Stem Length
Light management can be important in professional Optimo production.
During autumn and winter, when natural days are short, night-interruption lighting can be used to encourage sufficient stem length.
Professional production recommendations suggest night-interruption lighting approximately from 22:00 to 02:00 for at least three weeks after transplanting.
Once plants have reached approximately two-thirds of the desired stem length, shorter-day conditions can be used. Short days help improve flowering uniformity and can reduce finishing time.
For home gardeners growing the plants during the natural spring and summer season, specialised photoperiod control is generally not necessary.
Time to Flower
Optimo Red requires approximately:
18–21 weeks from sowing to flowering
14–16 weeks from transplanting to flowering
Actual timing depends on temperature, day length, sowing season and growing conditions.
The Optimo and Optimo α Alpha series are approximately 5–10 days later to flower than the Fujimi series.
Growing for Cut Flowers
Choose a position with plenty of light and good air circulation.
Plants are suitable for relatively dense planting, but good airflow remains important for maintaining healthy foliage and reducing disease pressure.
Consistent moisture and balanced nutrition encourage strong stems and high-quality flowers. Avoid prolonged waterlogging and extreme fluctuations between very wet and very dry growing conditions.
With its spray-type growth habit, Optimo Red produces multiple large flowers concentrated toward the upper part of the stem, creating naturally full stems for bouquet work.
Pests and Diseases
Although Optimo offers improved resistance, good crop management remains important.
Potential problems include Botrytis, rust, Fusarium and Pythium, as well as calcium or boron deficiencies.
Possible pests include spider mites and leaf miners.
Regular crop inspection, good air circulation, appropriate watering and rotation of production areas help maintain healthy plants.
Why Grow Optimo Red?
Professional China Aster for cut flowers • Rich red colour • Large 6–9 cm flowers • Unique chrysanthemum-shaped blooms • Spray-type growth • 60–75 cm tall • Reduced basal branching • Abundant top flowering • Suitable for high-density planting • Strong resistance to Fusarium • Lower susceptibility to Botrytis • Excellent for bouquets and professional floristry
Callistephus chinensis Optimo Red is an excellent choice for growers looking for professional China Aster seeds with large red flowers, spray-type growth and improved disease resistance. Its distinctive chrysanthemum-shaped blooms, strong cut-flower performance and intense red colouring make it a valuable addition to summer and autumn cut flower collections.
