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Growing callistemons in Australia


April 26, 2023


The Searles Gardening Team

Callistemons, commonly known as bottlebrushes, are a popular group of plants in Australia, known for their unique bottle brush-shaped flowers.

They are similar in appearance to Melaleucas, and in some cases, some Callistemons have been renamed as Melaleuca based on their DNA. Bottlebrushes can range in size from small shrubs like Callistemon 'Little John' which grows up to one meter, to weeping bottlebrush that can reach up to eight meters in height. They offer a wide range of flower colours including white, green, red, pink, mauve, and lemon.

One interesting aspect of bottlebrushes is their ability to adapt to different growing environments. For example, Callistemon 'Endeavour' is extremely frost hardy and drought resistant when mature, while the Alpine Bottlebrush Callistemon pityoides is native to wetlands and can thrive in sphagnum bogs and creek beds, but can also adjust to drier conditions. It's important to pay attention to the preferred soil types of each bottlebrush variety when choosing them for your garden, as they can range from moist clay to bogs to sandy soils.

Contrary to the common myth that natives don't require pruning, bottlebrushes benefit from regular pruning to maintain their shape and height, especially if used as screens or hedges. Prune them after flowering and fertilise them with a native plant fertiliser such as Searles Native Plant Food, which is organically based, every 8-10 weeks from spring to autumn. Another option is to use a controlled-release fertiliser like Searles Robust Natives Plants, which only needs to be reapplied every 6 months and doesn't have a strong odour.

Bottlebrushes can be susceptible to pests such as sooty mould, which is caused by honeydew produced by insects like scales, aphids, or mealybugs. Ants are often seen attending to these pests, so it's important to treat the plant for the underlying insect issue. Another pest to watch out for is sawflies, also known as spitfires, which are the offspring of sawflies and can skeletonize or eat the leaves of bottlebrushes. They emit an irritating fluid when disturbed, so caution is advised. There are parasitic wasps that can help control sawfly populations, but if immediate action is needed, spraying may be necessary.

Bottlebrushes are widely used in gardens and parks due to their versatility and stunning colours, which attract wildlife. With proper care including water, fertiliser, and pruning, they can mature into iconic Australian plants that add beauty and vibrancy to any landscape.

Popular Callistemon varieties

Callistemon 'Hot Pink' - A hot pink bottlebrush, flowering in spring.

Callistemon 'King's Park' - Large bright dark red flowers in spring and summer on a large shrub.

Callistemon 'Little Robyn' - Compact native shrub, large ruby flowers from peachy buds from autumn to spring.

Callistemon 'Mary Mackillop' - Vivid scarlet brushes appear during spring. Dense bright green foliage and soft new growth.

Callistemon 'Sugar Candy' - An abundance of pink flowers appear during spring and summer. Grows quickly and densely to provide screening, up to 3m tall.

Callistemon 'Little John' - Small compact bottlebrush to under 1m with scarlet red flowers.