Bottle Brush shrubs are one of the hardiest of Australian native plants. There are a variety of Bottle Brush plants (botanical name Callistemon) from tall shrubs, to low shrubs, to ground covers. This ease of cultivation and range of uses means that growing Callistemon bottle brush plants is a great way to raise native Australian plants in the home garden.
Callistemons can also grow in a variety of climatic zones from tropical right through to cool temperate regions making Bottle Brushes one of the most grown of all Australian natives. This makes them a popular shrub not only in Australia, but all around the world.
Callistemons are very easy to grow, and have few pest problems. Callistemons will grow in a variety of soils from sandy soils right through to heavy clays (where few other plants will grow).
Callistemons are also drought tolerant plants and will take extended periods of dry weather. Added to this they have fantastic flowering features, producing masses of Bottle Brush flowers at various times of year (mostly in the warmer months).
Generally speaking Callistemons are low maintenance plants. They generally do not require pruning with their natural shape being the most preferred and suitable for most gardens.
However, they can be pruned if required to keep them more compact. Pruning is generally done after flowering.
Callistemons can be used as screen plants or hedges or just as a feature plant. They generally live between 15 and 45 years.
Hedging and Screening
Bottle brush Callistemons, make excellent screen plants as they grow quickly and provide a good thick flowering screen.
Many varieties only grow to around 3 metres tall, so making them an excellent plant to create a visual screen. Callistemons, however, do drop a lot of flowers and when this occurs it can be messy.
Most gardeners (ourselves included) are happy to put up with this irritation because Bottle Brushes look so spectacular and are so low maintenance. It’s a small price to pay.
Callistemons can be hedged, however due to pruning process the flowers stems are cut off and as a result the plants do not develop flowers unfortunately.
Callistemons are much better grown in a natural informal shape when grown as a hedge. However, a periodic trim each year in autumn will assist the plant to become more compact.
How to plant Bottle Brush Callistemons
The planting process for Callistemons is relatively easy. As they are so very hardy, Callistemons do not require any special planting techniques.
However, when planting ensure that you dig a hole twice the size of the pot and backfill with a good planting mix. Callistemon plants will respond well to organic fertilisers (eg. manures), so mix some manure in with your planting mix.
With taller growing Callistemon Bottle Brush plants
it is important to stake them.
The standard method is to use two stakes: Position one on each side of the plant, a short distance out from the stem and tie well (use plant ties). In some situations a single stake will be fine, however it is important to remove it once the plants is showing signs of establishing, so the roots can spread.
Water well for the first couple of months. Once the plant has started developing roots, the shrub will generally look after itself.
How to fertilise Bottle Brush Callistemons
Another bonus in growing Callistemon Bottle Brush plants is that they do not require a great deal of fertiliser. Generally they will grow well on most soils and gain enough nutrients from the existing soil.
However, in situations where the soil is poor and impoverished, Callistemons can be fertilised with organic or a general purpose garden fertiliser.
Any organic fertiliser can be used, even chicken manure. Be careful to not over-fertilise: add the fertiliser in stages throughout the year.
Spring and autumn are the best times to fertilise Callistemons. Australian native fertilisers are also excellent for Callistemons and can be applied twice a year, in spring and autumn.
Varieties of Bottle Brush Callistemons
There are now many varieties of Callistemon available in today’s plant market.
You can find small tree varieties of 5m, right down to small shrubs around 1m. There are also some ground cover varieties.
Callistemons come in a multitude of colours including reds, pinks, whites, yellows and purples. They are used extensively by local councils as street trees due to their hardiness and low maintenance.
Some of the varieties like “wilderness white” and “wild fire” grow only to 2 metres and these have become very popular as garden shrubs and hedge plants.
See below for descriptions of some of the more popular varieties:
Callistemon citrinus Burgundy
A particularly hardy variety of Bottle Brush. Develops burgundy flowers in spring and summer. Plants grow to around 3 metres tall. Pruning is not required, however if pruning is required then prune after flowering.
Callistemon “Candy Pink”
A popular variety of Bottle Brush. Pink flowers develop in spring and summer. Plants grow to around 3 metres.
Callistemon “Captain Cook”
A popular variety of Bottle Brush. Produces red flowers throughout the warmer periods of the year. Plants grow from around 2m up to 4 metres tall. Does not require a great deal of pruning, but you prune after flowering if required.
Callistemon “Cedar Creek”
A hardy variety of Callistemon. Growing to around 5m.
Callistemon “Champagne Pink”
A weeping form of Callistemon. Shrubs grow to around 4 m.
Callistemon citrinus “Endeavour”
A popular variety of Bottle Brush which grows from around 2 to 3 metres. Plants produce red flowers through the warmer times of the year.
Callistemon “Clear view white”
Growing Callistemon Bottle Brush plants of this variety gives you a point of difference as it is an interesting white form of Bottle Brush. White flowers are developed in spring and summer. Plants grow to around 3 metres.
Callistemon “Dawson River Weeper”
A larger growing Bottle Brush that grows to around 5 metres. This is a popular variety of Callistemon which is grown extensively as a street tree. Plants are particularly drought tolerant and produce red flowers throughout the spring and summer.