China Aster 'Giants of California' Seeds

Callistephus chinensis 'Giants of California' is a Half-Hardy Annual (H2), meaning it's grown from seed each year and will not survive British winter frosts. However, this annual habit is actually brilliant—you can enjoy completely fresh, disease-free plants each season and never worry about them becoming woody, needing division, or exhausting the soil!

CRITICAL: Not to be Confused with Perennial Asters! China Asters (Callistephus chinensis) are completely different from the perennial "Michaelmas Daisies" (Aster/Symphyotrichum species) that bloom in autumn borders. China Asters are annual plants native to China and Korea, belonging to the daisy family (Asteraceae). They've undergone extensive horticultural breeding to create today's exceptional commercial cut flower varieties like 'Giants of California'!

The "Giants of California" Story: This variety was developed in Santa Maria, California—the heart of America's commercial cut flower industry—specifically for professional growers supplying florists and flower markets. The breeders had one goal: create the ULTIMATE cut flower Aster with maximum size, maximum stem length, maximum vase life, and maximum "wow factor." After decades of selection and refinement, 'Giants of California' emerged as the undisputed champion! The variety delivers everything commercial growers demand: blooms up to 12cm across (genuinely massive!), stems 60-70cm long (perfect for tall vases and wedding arrangements), exceptional wilt resistance, long vase life (up to 2 weeks!), and that show-stopping "ostrich plume" petal structure that looks incredibly exotic and sophisticated.

The "Ostrich Plume" Petal Structure: What distinguishes 'Giants of California' from other China Aster varieties (like 'Duchess' or 'Peony Mix') is the unique petal form. Instead of the tight, incurved, chrysanthemum-like petals of peony types, 'Giants of California' produces masses of longer, looser, more feathery petals that curve and twist in different directions, creating a shaggy, textured, almost "feather duster" appearance. The flowers are so packed with petals that the yellow centre is completely hidden (rarely visible even when flowers are past their peak), giving them that luxurious, fully double, pom-pom appearance. This "ostrich plume" structure not only looks spectacular but also contributes to the exceptional vase life—the looser petal arrangement allows better water uptake and reduces petal rot!

The Sophisticated Colour Palette: Unlike seed mixes that offer every colour under the sun (which can look chaotic and overwhelming), 'Giants of California' delivers a carefully curated palette of just 5 harmonious shades: Rose-pink (soft, elegant pink), Violet-purple (rich royal purple), Soft peach (delicate peachy-apricot), Deep crimson-red (vibrant ruby-red), and Pure white (clean snow white). These colours work beautifully together in mixed bouquets, creating sophisticated, florist-quality arrangements rather than garish rainbow explosions! The palette has an autumnal, jewel-toned quality that's perfect for late-summer and early autumn weddings, events, and seasonal decorating.

Late-Season Champions: One of the China Aster's greatest assets is its timing. Whilst most summer annuals (Cosmos, Zinnias, Marigolds) begin in June-July, China Asters hit their peak from August through October—providing that crucial "second wave" of fresh colour just when early bloomers are starting to fade. For cutting gardens, this late timing is absolutely invaluable—you get spectacular blooms when dahlia season is winding down but before chrysanthemums reach their peak, filling that awkward late-summer/early-autumn gap perfectly!

China Asters need a little warmth and care to get started, but once established they're remarkably robust and reliable performers. The key is giving them that critical early boost indoors before transplanting to the garden.

How to Sow:
Sow indoors from March to April (6-8 weeks before your last expected frost date). Fill seed trays or modules with good quality seed compost and water thoroughly. Sow seeds onto the surface of moist compost and cover with a fine sprinkling of vermiculite (approximately 3mm)—just enough to barely cover the seeds. China Asters germinate best with light covering, not complete burial or full surface exposure. Place in a propagator or cover with a clear lid to maintain humidity. Maintain a constant temperature of 18-21°C (65-70°F)—a heated propagator or warm windowsill is ideal. Keep the compost consistently moist but never waterlogged. Germination is usually quite reliable and takes 10-14 days.

Pricking Out & Growing On:
When seedlings develop their first true leaves (the second set of leaves, after the initial seed leaves), carefully prick them out into individual 7-9cm pots. Handle seedlings gently by their leaves (never the delicate stems!) to avoid damage. Grow on in a bright, frost-free location (greenhouse, cold frame, or bright windowsill). Keep plants well-watered and begin feeding with a weak liquid fertiliser once they're established in their pots and showing active growth.

Hardening Off & Planting Out:
This is CRITICAL for success! China Asters are half-hardy and will be killed by frost, so do not rush to plant out too early. Begin hardening off in late May by moving plants outside during the day and bringing them in at night for 7-10 days. Plant out into final positions only after all risk of frost has passed (typically late May to early June for most of the UK). Choose a position in full sun for best performance—they'll tolerate partial shade but flower size, stem strength, and colour intensity will be significantly reduced. Space plants 30cm apart to allow good air circulation (this helps prevent fungal diseases, which China Asters can be susceptible to in overcrowded, humid conditions).

Soil Requirements:
China Asters prefer rich, fertile, moisture-retentive but well-drained soil with plenty of organic matter. Before planting, dig in generous amounts of well-rotted compost or manure to improve soil structure, fertility, and water retention. 'Giants of California' is a hungry, thirsty plant producing those enormous flower heads—it needs nutrient-rich, moisture-retentive soil to perform at its best! They grow best in neutral to slightly alkaline soil (pH 6.5-7.5) and can struggle in very acidic conditions. CRITICAL: Whilst they need moisture-retentive soil, drainage must still be good—they absolutely hate sitting in waterlogged soil, which quickly leads to root rot and wilt diseases. If you have heavy clay, improve drainage by incorporating grit and organic matter.

Watering & Feeding:
Water regularly and generously during the growing season, aiming to keep the soil consistently moist (especially during flowering). Water at the base of plants (not overhead) to keep foliage dry and reduce fungal disease risk. Feed every 2-3 weeks with a balanced liquid fertiliser once plants are established and beginning to form flower buds. When flower buds appear, switch to a high-potassium feed (tomato fertiliser) to encourage maximum flower size and colour intensity. This sustained feeding is particularly important for 'Giants of California' as they're producing those absolutely massive 12cm flower heads and need substantial nutrients to maintain vigour!

Support & Staking:
This is ESSENTIAL for 'Giants of California'! Despite having naturally sturdy stems, the sheer weight of those enormous 12cm flower heads combined with the tall 60-70cm height means support is absolutely necessary, especially in exposed positions or windy gardens. The best approach is to install support EARLY (don't wait until plants are falling over!): push short pea sticks or linking stakes around plants when they're 20-30cm tall, or use horizontal netting (10-15cm mesh) for them to grow through. This provides invisible support as the foliage grows up and disguises the stakes. For cutting gardens, horizontal netting at 30cm and 60cm heights creates perfectly straight stems ideal for bouquets!

Deadheading & Cut Flower Harvesting:
For garden display: Deadhead spent blooms regularly to encourage continuous flowering and keep plants looking tidy. For cutting gardens: Cut stems freely and frequently for bouquets—this actually encourages the plant to produce more stems, extending your harvest! Cut stems in early morning when flowers are just fully opening (when 3/4 of petals are open) for maximum vase life.

⚠️ Disease Rotation Strategy:
China Asters can be susceptible to aster wilt (Fusarium wilt), a soil-borne fungal disease. To minimise risk: rotate planting sites each year—don't grow China Asters in the same spot two years running. This simple practice dramatically reduces disease incidence. Modern varieties (like 'Giants of California') have been bred for improved wilt resistance, but crop rotation remains the best preventative measure. If wilt does occur (plants suddenly collapse and die despite adequate watering), remove affected plants immediately and dispose of them (don't compost). Choose a different planting site next year.

'Giants of California' creates stunning partnerships with complementary plants that enhance rather than compete with those massive, show-stopping blooms. All companion plants listed below are available from Bishy Barnabees!

• 🌿 Ammi Majus (Queen Anne's Lace): The ultimate filler! This is THE classic florist's combination for creating professional-quality arrangements. The lacy white umbrellas of Ammi act as the perfect filler foliage, softening the bold, solid shapes of the giant Asters in both vases and borders. The textural contrast is absolutely sublime: the substantial, architectural, pom-pom Aster blooms against the delicate, cloud-like, ethereal Ammi creates exactly the kind of layered, sophisticated look you see in high-end florist shops and wedding bouquets. Both flower simultaneously (July-October for Ammi, August-October for Asters), both have excellent vase life, both are beloved by pollinators, and both are cut-and-come-again plants that produce more stems the more you harvest! Plant them together in generous drifts (minimum 10 plants of each) for maximum cutting potential. Height-wise, Ammi grows taller (90-120cm) than the Asters (60-75cm), so plant Ammi at the back and Asters in front for perfect tiered planting. In bouquets, use roughly 60% Ammi to 40% Asters for that perfect florist balance of filler to feature blooms!
• 🧡 Calendula 'Indian Prince': The warm autumnal contrast! Both plants flower late into the season (Calendula June-November, Asters August-October), making them perfect partners for extending the cutting garden through autumn. The deep mahogany-orange and burnt-terracotta tones of 'Indian Prince' create a warm, rich contrast with the violet-purples and rose-pinks of the Asters—this is THE colour combination for late-summer and autumn weddings, harvest celebrations, and seasonal decorating! The combination has a sophisticated, jewel-toned, autumnal quality that feels elegant rather than garish. Both are exceptionally easy to grow, both are prolific producers (Calendula is famously productive!), both have excellent vase life, and both attract beneficial insects. Plant them together in sunny borders for that quintessential "autumn cutting garden" look. The rounded, daisy-like Calendula blooms provide shape contrast with the shaggy, pom-pom Asters, whilst the similar heights (Calendula 40-60cm, Asters 60-75cm) create visual cohesion.
• 🌻 Zinnia 'Giants of California': The California giants unite! For a spectacular "California-style" cutting garden, grow both 'Giants of California' varieties together—Asters AND Zinnias! Both were bred in California specifically for commercial cut flower production, both produce huge blooms on long sturdy stems, both have exceptional vase life, both are "cut-and-come-again" varieties, and both flower prolifically from mid-summer through autumn. The Zinnias bring warm tones (coral, orange, yellow, red, pink) whilst the Asters contribute the cool purples, violets, and refined rose-pinks, creating a complete colour spectrum! Together they provide continuous cutting material from July (when Zinnias begin) right through to October (when Asters finish), ensuring your cutting patch is productive for a full 4 months. This is the ultimate professional cutting garden combination!

Sow indoors March-April. Plant out late May-June (after last frost). Flowers August-October.