Camellia Japonica: Australian Growing Guide

The Camellia japonica, commonly known as Camellia, is a shrub that can reach up to 10m in height and spread out to 8m in width. It boasts a robustness rating of 7, making it notably frost-resistant.

Introduction to Growing Camellia japonica in Australia

Blooming and Pollination of the Japanese Camellia in Australia

In Australia, the Camellia japonica showcases its vibrant blooms during the cooler months, from late autumn (May) through to early spring (September). Its flowers are unique in that they possess both male and female reproductive parts, and bees play a crucial role in their pollination.

Soil Information for Camellia japonica

The Camellia plant thrives in various soil types, from light sandy to medium loamy textures. Good drainage is essential for its growth. It's adaptable to different soil pH levels, favoring acidic soils with a pH below 6 and neutral soils ranging from pH 6 to 8. Moisture-rich soils are its preference.

Ideal Planting Locations for the Japanese Camellia

While the common camellia has a preference for forested soil, it can flourish in warm, open loam, especially when enriched with leafmould. It thrives under the dappled sunlight of light woodlands and is adaptable to areas with a north-western exposure or even walls without direct sunlight.

Ornamental and Commercial Value of the Common Camellia

Camellia stands out for its decorative appeal. Numerous variants have been cultivated, primarily for their aesthetic significance, with many capable of withstanding direct sunlight. In Asia, Camellias hold commercial importance, primarily due to the valuable oil extracted from their seeds.

Subspecies Insights into Camellia japonica

One notable subspecies, C. japonica macrocarpa. Masam., is characterized by its larger fruit, resembling miniature apples. Another variant, C. japonica rusticana (Honda.)Kitamura, is recognized for its robust nature. Originating from Northern Japan, it's adapted to higher elevations and endures extended snow-covered winters.

Cultivars of Camellia japonica

• 'Alba Simplex' - This cultivar has been seen on a number of occasions bearing good crops of fertile seed.
• 'Coppelia' - This cultivar has been seen on a number of occasions bearing good crops of fertile seed.
• 'Guilio Nuccio' - A single-flowered cultivar originating in California, it regularly sets seed in Porthpean garden in southern Cornwall.
• 'Jupiter' - This single-flowered cultivar regularly sets seed in British gardens.

Propagation Techniques for the Common Camellia

Seed: can be sown as soon as it is ripe in a greenhouse. Stored seed should be pre-soaked for 24 hours in warm water and the hard covering around the micropyle should be filed down to leave a thin covering.

It usually germinates in 1 - 3 months at 23°c. Prick out the seedlings into individual pots when they are large enough to handle and grow them on in light shade in the greenhouse for at least their first winter.

Once the seedlings have grown to a height of over 15cm, they can be transplanted to their permanent locations. It's advisable to provide them with some protection against the cold during their initial one to three years outdoors to ensure their healthy growth.

Cuttings from Almost Ripe Wood: In February or March, take cuttings of nearly mature wood, measuring 10 - 15cm, ensuring they have a heel. Place these cuttings in a shaded frame. This method generally has a high success rate, though it might be a bit slow.

Cuttings from Firm Wood: Towards the end of December, cut firm wood segments of 7 - 10cm, again with a heel, and place them in a frame. It's recommended to keep these cuttings in a cool greenhouse during their first year to promote optimal growth.

Leaf-Bud Cuttings: In January or February, you can also opt for leaf-bud cuttings. Place them in a frame to encourage rooting.

Pruning and Deadheading Camellia japonica

Pruning:

Pruning is essential for maintaining the shape, size, and health of your Camellia japonica. Regular pruning helps to encourage new growth, improve air circulation, and remove any dead or diseased branches.

1. When to Prune: The best time to prune Camellia japonica is in late winter or early spring, just after the plant has finished flowering. This timing ensures that you won't accidentally cut off any of the upcoming season's buds.
2. How to Prune: Start by removing any dead, diseased, or crossing branches. Then, shape the plant by cutting back any long, leggy branches. Always make your cuts just above a leaf joint or bud.
3. Thinning: If your Camellia has become too dense, you can thin out some of the branches to improve air circulation and light penetration. This can help prevent diseases and ensure a healthier plant.

Deadheading:

Deadheading, or the removal of spent flowers, can be beneficial for Camellia japonica, though it's not strictly necessary.

1. Benefits: Deadheading can help the plant look tidier and can potentially encourage a second, though smaller, bloom in some varieties. It also prevents the plant from putting energy into seed production, directing it instead to root and foliage growth.
2. How to Deadhead: Gently pinch or snip off the faded blooms, being careful not to damage the nearby buds or leaves.

General Tips:

• Always use sharp and clean pruning tools to ensure clean cuts and prevent the spread of diseases.
• If you're unsure about a particular cut, it's better to err on the side of caution and cut less rather than more. You can always trim more later if needed.
• After pruning, it's a good idea to give your Camellia a boost with some balanced fertilizer to support new growth.

Pests and Diseases Affecting Camellia japonica

Camellia japonica, like many plants, can be susceptible to a range of pests and diseases. Here's a brief overview:

Pests:

• Camellia Aphid (Myzus persicae): These tiny green insects can be found on the undersides of leaves, causing them to curl and become discolored. They can be controlled using insecticidal soap or neem oil.
• Tea Scale (Fiorinia theae): These are small, oval-shaped insects that attach to the undersides of leaves, leading to yellow blotches on the upper surface. Regularly inspecting plants and removing affected leaves can help manage this pest.
• Red Spider Mite (Tetranychus urticae): These microscopic mites can cause the leaves to take on a bronze hue. Increasing humidity and using miticides can help control their population.

Diseases:

• Camellia Petal Blight (Ciborinia camelliae): This fungal disease causes brown spots on the petals, which eventually lead to the flower collapsing. To manage this, remove and destroy affected flowers and apply appropriate fungicides.
• Root Rot: Caused by various fungi, this disease affects the roots, leading to yellowing leaves and stunted growth. Ensuring good drainage and avoiding over-watering can help prevent this issue.
• Leaf Gall: This disease causes leaves to become thickened, pale, and distorted. It's essential to remove and destroy affected leaves to prevent its spread.

Regular inspection of your Camellia japonica and maintaining good gardening practices can help in early detection and management of these pests and diseases, ensuring your plant remains healthy and vibrant.

Edible Uses of the Japanese Camellia

The seeds of the Camellia yield an edible oil, commonly referred to as 'tsubaki oil'. Its dried blossoms can be cooked and consumed either as a vegetable or combined with sticky rice to prepare a traditional Japanese delicacy known as 'mochi'. Additionally, its leaves can serve as an alternative to tea.

Medicinal Uses of Japonica

Camellia flowers possess multiple medicinal properties, including astringent, anti-bleeding, blood-clotting, soothing, and tonic effects. When combined with sesame oil, they offer a remedy for burns and scalds. Additionally, research indicates potential anticancer properties in the plant.

References

Trees and Shrubs Hardy in Great Britain. Vol 1 - 4 and Supplement.

• Bean. W.
• Author: Bean. W.
• Publisher: A classic with a wealth of information on the plants, but poor on pictures.
• Date of Publication: 1981

Flora of Japan. (English translation)

• Ohwi. G.
• Author: Ohwi. G.
• Publisher: The standard work. Brilliant, but not for the casual reader.
• Date of Publication: 1965

The New RHS Dictionary of Gardening. 1992.

• Huxley. A.
• Author: Huxley. A.
• Publisher: Excellent and very comprehensive, though it contains a number of silly mistakes. Readable yet also very detailed.
• Date of Publication: 1992

Wrapping up How To Grow Camellia Japonica in Australia

Camellia japonica has vibrant blooms, rich history, and diverse uses make it a cherished addition to gardens worldwide. Whether you're growing it for its aesthetic appeal, its medicinal properties, or its rich cultural significance, it's essential to understand its care requirements and potential challenges.

With the right knowledge and attention, this plant can thrive and become a centerpiece in any garden setting. Throughout the world of gardening, few plants hold the allure and charm of the Camellia japonica.