Aster

Family: Asteraceae

Genus: Callistephus

Species: chinensis

History

Asters bring late-season colour with their daisy-like blooms and star-shaped appeal—the name comes from the Greek word for "star." Long grown in European cottage gardens, asters are now a staple in Australian perennial beds, blooming when many other flowers fade and attracting bees by the dozen.

Sowing Calendar

Best Months to Plant – Aster
Climate ZoneJanFebMarAprMayJunJulAugSepOctNovDec
Cool/Mountain
Temperate
Arid
Subtropical
Tropical
Cool/Mountain – Aster
MethodJanFebMarAprMayJunJulAugSepOctNovDec
Start in trays
Plant out transplants
Direct sow
Temperate – Aster
MethodJanFebMarAprMayJunJulAugSepOctNovDec
Start in trays
Plant out transplants
Direct sow
Arid – Aster
MethodJanFebMarAprMayJunJulAugSepOctNovDec
Start in trays
Plant out transplants
Direct sow
Subtropical – Aster
MethodJanFebMarAprMayJunJulAugSepOctNovDec
Start in trays
Plant out transplants
Direct sow
Tropical – Aster
MethodJanFebMarAprMayJunJulAugSepOctNovDec
Start in trays
Plant out transplants
Direct sow

Where to Plant

Containers & Pots

Containers & Pots
• Portable planting vessels suited for patios, balconies, and small areas
• Provide complete control over soil composition and drainage
• Great for herbs, greens, compact vegetables, or ornamental plants
• Allow plants to be moved to follow sun, shade, or seasonal conditions

Shady Spots & Herb Gardens

Shady Spots & Herb Gardens
• Areas receiving dappled or indirect sunlight, often near trees or buildings
• Best for shade-tolerant herbs like mint, parsley, or greens like spinach
• Helps prevent sun stress and conserves moisture
• Often used in cooler corners of the garden

Edges

Edges
• Narrow growing spaces along borders, fences, or pathways
• Perfect for low-growing or decorative plants like alyssum or herbs
• Helps soften garden boundaries and attract beneficial insects
• Makes efficient use of underutilised garden space

Borders & Companion Rows

Borders & Companion Rows
• Found along the edges of garden beds, paths, or between main crops
• Ideal for herbs, flowers, or pest-repelling plants that support the main crop
• Helps attract pollinators and beneficial insects
• Makes good use of smaller spaces and improves overall garden health

Hanging Baskets & Vertical Planters

Hanging Baskets & Vertical Planters
• Containers suspended above ground or mounted vertically to save space
• Ideal for trailing or compact plants such as strawberries, herbs, or flowers
• Enhance airflow and accessibility for tending
• Require more frequent watering due to increased exposure

Pre-treatment

None Identified

There are no pre treatments required for germination.

Sowing Method

Start in Trays

• Fill seed trays or punnets with quality seed-raising mix
• Sow seeds at the correct depth—refer to seed packet for guidance
• Place trays in a warm, sheltered location with good light
• Mist or bottom-water to avoid disturbing small seeds
• Transplant seedlings once they develop 2–4 true leaves

Direct Sow

• Sow seeds directly into prepared garden soil or outdoor containers
• Best for plants that dislike transplanting, such as root vegetables and beans
• Loosen soil and remove weeds before sowing
• Sow at the recommended depth and spacing, then water gently
• Keep the area moist until germination and thin seedlings if needed

Watering

Medium

• Benefits from regular watering, especially during active growth or flowering
• Soil should remain moist but not soggy—allow topsoil to dry slightly between waterings
• Ideal for most vegetables, herbs, and flowering annuals
• More frequent watering may be needed during hot or windy weather
• A layer of mulch can reduce water loss and improve consistency

Fertilisation

Frost

Frost Tolerant

These plants can tolerate light to moderate frosts and may survive through cooler seasons.

Maintenance and Harvesting

Aster benefits from division every few years to prevent overcrowding. Deadhead to extend flowering and cut back in late autumn.

Pests and Diseases

Aphids

Aphids are tiny, soft-bodied insects that cluster on new growth and the undersides of leaves. They suck sap from plants, causing leaves to curl, yellow or become distorted. As they feed, they excrete sticky honeydew that encourages sooty mould, and colonies can build quickly in warm weather.

Start with organic controls: blast colonies off with a firm jet of water, encourage beneficial insects like ladybirds and lacewings, and spray neem oil or insecticidal soap to disrupt feeding. Keep plants well watered and avoid excess nitrogen that promotes soft growth. If pressure remains high, selective chemical sprays can be used sparingly, taking care to protect pollinators and beneficials.

Leaf spot

Leaf spot describes several fungal or bacterial diseases that create dark, often round lesions on foliage—sometimes with yellow halos. Severe infections cause premature leaf drop and reduced vigour, especially during warm, wet spells or when leaves stay damp.

Reduce spread by removing infected leaves, watering at the base, and spacing plants for airflow. Mulch to limit soil splash and rotate crops. Organic preventatives include copper and sulfur sprays applied early. If disease escalates, registered fungicides offer a chemical backup.

Crown / root rot (Wet)

Crown and root rots are caused by water‑loving fungi that attack stems at the soil line and roots below. Plants yellow, wilt, and eventually collapse because their roots can no longer supply water and nutrients—most common in heavy, waterlogged soils.

Prevention is key: improve drainage, raise beds, and water deeply but less often. Avoid injuring stems at the soil line and rotate away from affected beds. Solarising soil in summer can knock back pathogens. Chemical drenches have limited benefit in home gardens and are best used preventatively rather than curatively.

Powdery mildew

Powdery mildew appears as a white, talc‑like coating on leaves and stems. It thrives in warm days, cool nights, and still air, and can weaken plants by reducing photosynthesis, leading to yellowing and early leaf drop.

Prune for airflow, avoid overhead watering, and remove badly affected foliage. Organic sprays such as milk solution, potassium bicarbonate, sulfur, or neem help suppress outbreaks. Chemical fungicides are effective when started early, but use sparingly to preserve beneficial organisms.

Thrips

Thrips are slender insects that rasp and suck plant tissues, leaving silvery streaks and distorted growth on leaves and flowers. They can also transmit plant viruses.

Use blue or yellow sticky traps to monitor and reduce numbers, weed around beds, and encourage beneficials like minute pirate bugs. Neem oil and insecticidal soap offer organic suppression. If needed, use registered insecticides and rotate modes of action to avoid resistance.

Rust

Rust diseases produce raised orange‑brown pustules on leaves and stems. Spores disperse easily on wind and water, causing repeated reinfection and gradual weakening of plants.

Remove infected material and avoid wetting foliage. Grow resistant varieties where possible and rotate crops. Organic sulfur or copper sprays can protect new growth; systemic fungicides are a chemical fallback if rust persists.

Aster yellows

Aster yellows can affect plant health and yields in home gardens. Typical symptoms include slowed growth, discolouration, and reduced productivity, often triggered by weather, nutrition, or cultural conditions.

Start with cultural fixes: rotate crops, improve soil with compost, water consistently, and choose resistant varieties. Organic sprays or amendments can reduce severity; chemical options are a last resort and should be used carefully and in accordance with labels.

Growing Tips

• Aster can flop without pinching; trim early growth to keep compact.
• Aster flowers less in shade; choose a sunny spot.
• Aster crowds quickly; divide clumps every few years.

Browse Aster Seeds