Chrysanthemums: Growing and origins

Varieties of chrysanthemums

In Australian gardens, chrysanthemums are commonly grown as either annuals or perennials, depending on the variety and climate. Some varieties thrive year-round in the ground, while others are better suited to pots, especially in cooler regions where frosts may be an issue.

There are over 40 species of chrysanthemums, with countless hybrids offering a wide array of colours, flower shapes, and blooming periods. Their blossoms range from traditional daisy-like forms to pompons and intricate spider shapes.

Some popular varieties in Australia include:

• Garden chrysanthemums (Chrysanthemum morifolium): These are frost-tolerant and perfect for garden beds or pots. Their size can vary, but typically range from 30 to 90cm in height and spread.
• Early flowering varieties: Perfect for spring planting, they include the vibrant tricolour daisy (Chrysanthemum carinatum), which grows to approximately 60cm tall and features eye-catching blooms.
• Late-flowering varieties: These bloom well into late autumn and are a great addition to any garden. Varieties such as Chrysanthemum Peggy, with orange pompon-like flowers, are particularly frost-hardy and reach between 60cm and 90cm in height.

How to plant chrysanthemum flowers

Growing chrysanthemums is straightforward, thanks to the plant's versatility. These flowers thrive in well-draining, fertile soil with a neutral to slightly acidic pH (6.0–7.0). Proper soil preparation is key to healthy growth and abundant blooms. Enrich sandy or clay soils with organic matter like compost or aged manure. For potted chrysanthemums, a high-quality potting mix with controlled-release fertiliser is ideal.

How to grow chrysanthemums from cuttings

Most gardeners prefer to grow chrysanthemums from cuttings rather than seeds. Cuttings root quickly, allowing for faster growth and better disease resistance. You should be able to find a variety of ready-to-plant chrysanthemum cuttings in your local nursery, making them an accessible choice for beginners.

How to grow chrysanthemums from seed

If growing from seed, sow seeds about one millimetre deep and 20 to 40cm apart into well-draining, fertile soil. Keep soil moist during germination, which should take about 10 to 14 days. Keep young seedlings protected from pests and winds until they are established.

When to plant chrysanthemums in Australia

For best results, plant chrysanthemums in spring after the risk of frost has passed. Ensure each plant has at least six weeks of frost-free weather to establish itself.

Where to plant chrysanthemums

Chrysanthemums need plenty of sunlight to grow and bloom successfully. Choose a location that gets at least six hours of direct sunlight a day. In shaded areas, plants can grow leggy and produce fewer flowers. Avoid planting in low-lying or waterlogged spots, as excessive moisture can lead to root rot. For gardens prone to strong winds, select sheltered positions to protect the delicate flower stems. If planting in pots, make sure the containers have good drainage. Space plants about 45 cm apart to allow for airflow and prevent overcrowding.

How to prune chrysanthemums

Young chrysanthemum plants can be pruned to encourage bushier growth. Use sharp and clean pruners or scissors to cut back the plant, cutting just above the leaf node. If you want to encourage larger flowers, remove some of the flower heads so the plant can concentrate all its energy into the remaining flowers. For more flowers, pinch the tips of new growth to encourage branching and create a fuller plant. Repeat the process when the new shoots reach seven to ten centimetres. This technique helps produce more flower buds.

Chrysanthemum care tips

Chrysanthemums are relatively low maintenance, but proper care ensures a healthy and vibrant display of flowers. Follow these tips for abundant blooms:

• Watering: Keep the soil evenly moist, but not waterlogged. Chrysanthemums dislike dry conditions but are equally sensitive to overwatering. Regular watering during summer helps sustain flowering. Avoid overwatering potted chrysanthemums, as soggy soil can stress the plants.
• Fertilising: Feed plants with a balanced liquid fertiliser every two weeks during the growing season. For garden beds, you can also use slow-release fertiliser at the start of the season to ensure a consistent nutrient supply.
• Pruning and pinching: Pinching back new growth when plants reach about 15 cm in height will promote bushier growth and more flowers.
• Deadheading: Remove dead flowers and foliage to encourage continuous blooming and prevent diseases.  Deadheading directs the plant’s energy toward producing fresh blooms rather than seed formation.
• Protection from the elements: For taller chrysanthemum varieties, consider staking the stems to prevent damage from wind or heavy blooms. Use soft ties to secure the plants without restricting growth.
• Timing: Chrysanthemums bloom best in response to shorter daylight hours, making them ideal for autumn gardens in Australia. Adjust your planting schedule to align with their natural growth cycle for the best results.

Common pests and diseases

While hardy, chrysanthemums can be susceptible to pests and diseases if not properly cared for. Common issues include:

• Aphids and spider mites: These pests suck sap from the leaves, causing them to yellow or curl. Treat infestations with insecticidal soap spray or neem oil.
• Powdery mildew: This fungal disease appears as a white coating on leaves and stems. Prevent it by watering the soil rather than the foliage and ensuring good airflow around plants.
• Root rot: Avoid planting chrysanthemums in poorly drained soil, as waterlogged conditions can lead to root damage.

Maintaining garden hygiene by clearing dead leaves and plant material helps prevent the spread of pests and diseases.

Overwintering chrysanthemums

In regions with mild winters, chrysanthemums can remain in the ground year-round. However, in areas prone to frost, they require extra care to survive the colder months. Here’s how to prepare your plants for winter:

1. Cut back the stems: Trim plants to about ten centimetres above the ground after the flowering season ends.
2. Mulch the base: Apply a thick layer of organic mulch, such as straw or bark chips, to protect roots from frost. Avoid using moisture-retentive materials to reduce the risk of rot.
3. Container plants: For chrysanthemums grown in pots, move the containers to a sheltered spot to shield them from frost. Water sparingly during this period to keep the soil just moist.

Quick facts about chrysanthemums

For a quick reference, here are some essential facts to remember when growing chrysanthemums in Australia:

• Blooming period: Late summer to autumn.
• Sunlight needs: At least six hours daily.
• Soil type: Well-drained, slightly acidic.
• Watering needs: Keep soil moist but avoid waterlogging.