- Propagation Of Bottlebrush Trees: Growing Callistemon From Cuttings Or Seed
- Propagation of Bottlebrush Trees
- How to Propagate Bottlebrush Trees from Seeds
- Growing Callistemon from Cuttings
- Growing Callistemon from Seed
- Byron Williams
- SelecTree: Tree Detail
- How to Take Bottle Brush Cuttings
- Bottle Brush Tree Overview
- Types Of Bottle Brush Tree
- Bottle Brush Tree Care
Propagation Of Bottlebrush Trees: Growing Callistemon From Cuttings Or Seed
Bottlebrush trees are members of the genus Callistemon and are sometimes called Callistemon plants. They grow spikes of bright flowers composed of hundreds of tiny, individual blossoms that appear in spring and summer. The spikes look like the brushes used to clean bottles. Propagation of bottlebrush trees is not difficult. If you want to learn how to propagate bottlebrush trees, read on.
Propagation of Bottlebrush Trees
Bottlebrush grow into big shrubs or small trees. They are excellent garden plants and can range from several feet tall to over 10 feet (3 m.). Most tolerate frost and require little care once established.
The blaze of flowers is spectacular in summer, and their nectar attracts birds and insects. Most species are frost tolerant. It is understandable that you might want to increase the number of these lovely trees in the backyard.
Anyone who has access to one bottlebrush tree can begin
propagating bottlebrush. You can grow new bottlebrush trees either by collecting and planting callistemon bottlebrush seeds or by growing callistemon from cuttings.
How to Propagate Bottlebrush Trees from Seeds
Propagating bottlebrush is easy with callistemon bottlebrush seeds. First, you have to look for and collect the bottlebrush fruit.
Bottlebrush pollen forms on the tips of the long, flower spike filaments. Each blossom produces a fruit, small and woody, that holds hundreds of tiny callistemon bottlebrush seeds. They grow in clusters along the flower stem and can remain there for years before the seeds are released.
Collect the unopened seeds and store them in a paper bag in a warm, dry place. The fruit will open and release the seeds. Sow them in well-draining potting soil in spring.
Growing Callistemon from Cuttings
Bottlebrush cross-pollinate readily. That means that the tree you want to propagate may be a hybrid. In that case, its seeds probably will not produce a plant that looks like the parent.
If you want to propagate a hybrid, try growing callistemon from cuttings. Take 6-inch (15 cm.) cuttings from semi-mature wood in summer with clean, sterilized pruners.
To use the cuttings for the propagation of bottle trees, you need to pinch off the leaves on the lower half of the cutting and remove any flower buds. Dip the cut end of each into hormone powder and plunge into rooting medium.
When you are growing callistemon from cuttings, you’ll have more luck if you cover the cuttings with plastic bags to hold in moisture. Watch for roots to form within 10 weeks, then remove the bags. At that point, move the cuttings outdoors in springtime.
Growing Callistemon from Seed
There is something magic about creating a beautiful Callistemon plant from a tiny seed whilst nature looks over your shoulder.
Callistemons are some of the easier of our native plants to grow from seed. Just sprinkle the seed onto some soil in a pot just like you do with poppy or petunia seed, add moisture and a little warmth and after two or three weeks – ‘bingo’, you have lots of little bambino callistemons, all competing to survive like young chicks in a nest. Whilst germination and the first two weeks are relatively straight forward, after that you do need to give your tiny Callistemon seedlings daily attention to ensure they are watered, have good air circulation, kept sheltered plus a little TLC and a dash of common sense, to grow them on successfully.
Because individual species of Callistemon come in a number of forms and hybridise so readily, you can’t be sure seed grown callistemons will be the same as the parent plant. So if you want to reproduce an exact replica of a particular Callistemon, it is essential you grow your new Callistemon from cutting material and not from seed. Unless the seed you plant is pure species seed, not contaminated by the pollen of other forms of Callistemon, the chances of producing plants quite different from the parent are the norm rather than the exception; which makes the practice of growing callistemons from seed all the more fascinating. It never ceases to amaze me the variety of seedlings that can be produced from a small amount of fertile seed; all sorts of shapes, sizes and forms. It’s a bit like a lucky envelope draw at the local show ; you just never know what you will get!.
“…..if you want to reproduce an exact replica of a particular Callistemon, it is essential you grow your new Callistemon from cutting material and not from seed. “
If your seed has come from a hybrid Callistemon often your seedlings may take on the features of one or the other of the parents or a combination of both – or produce a brand new hybrid where further cross pollination has taken place. This can be illustrated very effectively by planting some seed from the lovely brilliant red “Harkness” that originated in South Australia. Some of the seedlings appear to exhibit C.viminalis species features ie gently weeping foliage, while others seem to be of a more upright type along the lines of C.citrinus. From time to time the seed will throw up a seedling with very small leaves similar to the early forms of C.recurvus (originally C. “Tinaroo Falls”) just to add a little mystery and confusion to the plot. It’s just like a time machine, when your seed germinates and you get all these little seedlings, some showing features of callistemons of a by gone age.
The variability of brush colour in seedling grown plants is just as fascinating. Plant seed from a pink hybrid Callistemon and often the seedlings when they eventually flower will have brushes of various shades of pink, red and from time to time pure white. For example, seed I have planted from the lovely C. “Western Glory” (which has dark red brushes with a mauve tint), has produced seedlings which eventually flowered with brushes in shades of red, pink and mauve. On the other hand C. “Harkness” seedlings always seem to produce seedlings that have red brushes, which probably means both parents were red flowering callistemons. Another example that readily comes to mind is the well known group of Victorian callistemons of suspect C.citrinus origin, which have been available for many years in Melbourne. C. “Reeves Pink”, has clear pink brushes; seed from “Reeves Pink” is said to have produced two well known cultivars in “Mauve Mist” (pinkish-mauve brushes) and “Burgundy” (deep burgundy-red brushes). A lesser known seedling that “Reeves Pink” is said to have produced was “Starlight”, which had white brushes. It is also thought that another not so common Callistemon called “Violet Clusters” was a seedling of “Reeves Pink”.
An example of just how easily callistemons mate was given in a very interesting article by Norm McCarthy in the October 1998 issue of Native Plants for New South Wales titled “Strange but True”. It tells the story of how many years ago he planted some Callistemon seed from a packet labelled C.polandii (a beautiful red Callistemon from Queensland) which produced some seedlings with three distinct leaf forms and pink flower brushes. The first form was thought to be a relict form of C.citrinus, the second resembled an existing pink form of C.polandii. and the third form had foliage similar to C.pachyphyllus (NSW/Qld) and ended up appearing in the nursery trade as Callistemon “Pink Champagne”. All from the one packet of Callistemon seed! Fascinating isn’t it?
| Parents of many bottlebrush hybrids. Callistemon citrinus (left) and Callistemon viminalis (right).
Select the thumbnail image or plant names for higher resolution images (30k and 43k).
Callistemon “Western Glory” (left) and Callistemon “Violaceus” (right). Both of these need to be propagated by cuttings.
Select the thumbnail image or highlighted name for a higher resolution image.
The species of Callistemon that most commonly are alleged to have been involved in producing hybrids are the commonly grown C.citrinus and C.salignus (originating mainly from New South Wales), C.polandii (Queensland) and, of course, particularly the many forms of C.viminalis (Queensland). There is some botanical question as to whether C.viminalis should be classified as Melaleuca rather than a Callistemon because of the arrangement of its stamens, although in the garden it seems quite happy to inter- breed only with callistemons and not with melaleucas – but the botanists can work that one out.
While growing callistemons from seed is an interesting hobby it should not be forgotten there is an incredible number of Callistemon forms and cultivars growing out there in home gardens and available in nurseries. This has led to much confusion in defining the species under their correct botanical names and the many horticultural forms and cultivars. So as not to add to the confusion, when growing callistemons from seed, it is prudent to keep a record of the species or cultivar name of the parent plant(s) if known, the source or location from where the seed came and details of the Callistemon species or cultivars growing near the parent plant if you collected your own seed. In this way you will know your seedling’s pedigree if in fact it turns out to be a good one.
…..and who knows, with the passage of time you might find that tiny little seedling you germinated under plastic in a dish of water out the back, has turned into a magnificent hybrid every bit as good as some of the well known cultivars presently available in nurseries and written about in gardening magazines. The fascination of growing callistemons from seed!
From the September 2000 issue of “Growing Australian”, the newsletter of the Australian Plants Society (Victoria).
Australian Plants online – March 2001
Association of Societies for Growing Australian Plants
SelecTree: Tree Detail
Lemon Bottlebrush is commonly grown as a shrub, or as a single trunk tree standard. It is a tough, reliable evergreen species, attractive by nature of its red brushlike flower plumes, though it is considered quite common and not especially exciting otherwise. It is especially attractive to hummingbirds. It may require regularly scheduled light top-trimming (but not necessarily shearing) of vigorous top shoots to maintain its height below 25′.
Has fragrant Leaf.
Native to Queensland, New South Wales and Victoria in Australia.
Additional Common Names
CRIMSON BOTTLEBRUSH, LEMON BOTTLEBRUSH
Erect or Spreading with a Low Canopy.
Oval or Rounded Shape.
Has Evergreen foliage.
Height: 20 – 25 feet.
Width: 25 feet.
Growth Rate: 36 Inches per Year.
Longevity 40 to 150 years.
Leaves Lanceolate, Medium Green, No Change, Evergreen.
Flowers Showy. Red. Flowers in Spring or Summer. Has perfect flowers (male and female parts in each flower).
Brown Capsule, Small (0.25 – 0.50 inches), fruiting in Fall Wildlife use it.
Bark Light Green or Light Gray, Exfoliating or Striated.
Shading Capacity Rated as Dense in Leaf.
Litter Issue is Flowers.
I have a beautiful shrub in my front garden which is admired by all who see it in flower. So much so, that when it’s in full swing in May, I put a large name label on it so that people can read what it is, which at least stops some of them from knocking on the door to find out what’s making the red fireworks. The name of the plant I’m talking about is Callistemon Viminalis ‘Captain Cook.’ I put it in 16 years ago, when we first moved to this house — back then it was something of a novelty (the Australian man who ran our local plant shop also introduced me to tree ferns). Thankfully, these days you can find different species of Callistemon in all good garden centres, but people are still worried about how to look after them.
In their native Australia, bottlebrushes come in different shapes and sizes: some with weeping habit, others with pink rather than red flowers. They tend to cross-fertilise in the wild, so, if you want a true replica of the plant you are looking at, the only way to do it is with cuttings. It is possible to take cuttings from semi-ripe wood in July or August, but I’ve found that on the whole these have a very poor success rate compared to other shrubs.
The best method for Callistemon seems to be propagation by seed.
I’m sowing two lots in the greenhouse this February, the first is Callistemon Rigidus from Johnson’s seeds. The seed is so fine it should be sown on the surface of finely sieved compost. Unlike other seeds, bottlebrush seems to like sitting in a tray of water while it’s making its mind up to germinate. Take the seed tray out of the water once the seedlings have emerged and pot them on individually. The other batch I’m sowing in the greenhouse is from seed taken from the plant in my front garden. If you look at a bottle brush stem, you will see two (occasionally three) different groups of round seedheads. Those produced the previous year are the group closest to the tip, those produced two years ago, and the most viable in fact, are the seed heads further along the stem.
In order to collect the seed you will have to cut a stem then bring it into the greenhouse. After a day or two, the seed pods open and release their fine, dusty seed. These are sown as per above.
Bottlebrushes tolerate a range of soils (though they are not keen on chalk). They do need some frost protection, especially if you live further north, and young plants are more vulnerable to the cold than older ones. Once it gets going, Callistemon could not be an easier and less demanding plant, responding well to a good prune in late summer if you need to keep it in shape.
How to Take Bottle Brush Cuttings
It is quick and easy to take bottle brush cuttings and saves a considerable amount of money when you want to create a screen or hedge with these beautiful Australian natives.
The bottle brush (callistemon) is a drought hardy plant that thrives in most soils and positions and even tolerates poor soils. Apply slow release fertiliser for native plants twice a year (beginning of spring and autumn) for optimum results. Do not use other types of fertiliser as native plants do not tolerate phosphorus well.
The stunning flowers are attractive to nectar eating birds and provide a brilliant display. There are many different varieties and colours to choose from such as candy pink, lemon or the traditional red bottle brush.
- Pruners – Try these ratchet pruners which are easier on your hands from Amazon. (Paid link)
- Potting Mix
- Plant Cutting Powder (Paid link)
Time needed: 20 minutes.
How to Take Bottle Brush Cuttings
- Find an Existing Plant
To take bottle brush cuttings, first you will need to find an existing plant or buy a plant you like. Even if the plant is young, cutting back a bottle brush will make it bushier, so you are helping the plant by taking the cuttings.
- Prepare the Pots
Fill a few pots with potting mix remembering that not all cuttings will make it, so it’s always best to take more than you need. You can add a small amount of slow release fertiliser for natives to the pots if you have it, but they will be fine without.
Water the pots and make a 1 inch deep hole in the centre with your finger. This way you won’t disturb the cutting powder when the cutting is planted.
- Look for New Growth that Springs Back
Look for healthy growth, but you do not want new growth that is still floppy. The newest growth doesn’t seem to take as well. You want growth that is in the next stage. The stem will be light brown, not light grey or silver and will spring back when bent.
- Take the Cutting
The cutting should be 5 cm (2 inch) to 10 cm (4 inch) long. Cut on an angle then take off the bottom leaves leaving the top 3 or four.
Moisten the end then dip in the cutting powder and shake off the excess.
- Plant in the Pot
Place cutting in the hole you have made in the pot then gently push the soil around it.
Place pots on a tray with water so they stay moist and keep in a warm, frost free position.
It can take many weeks to grow the roots. Gently tug the plant and if it doesn’t give easily, the roots have grown otherwise it will need more time. Once you are confident the cutting has roots, pot it up to a larger pot then include slow release native fertiliser for best results.
Do you need pots? Try these great value pots from Amazon. (Paid link)
To save or print this guide on How to Take Bottle Brush Cuttings, here is the PDF Version
Bottle brushes are great plants for dry conditions, try this guide for more tips: Gardening in Dry Conditions
Looking to include more native plants in your garden? Try this guide on Woolly Bush Cuttings or growing Kurrajong Trees from Seed.
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Named for their bottle brush-shaped flowers, this plant can grow as a bottle brush tree or a shrub. Originating in Australia, there are around 50 species of bottle brush plants, each one with a slightly different growth pattern.
Great attractors of pollinators, the bottle brush tree is a close relative of the paperbark melaleuca. It’s such a close relative, in fact, that all but four varieties have been moved to the melaleuca category!
While commercial nurseries continue to sell most bottlebrush trees as callistemon, most scientists and botanical gardens have made the transition to new names. No worries, though – I’ll make sure you have both to choose from.
No matter if you choose to grow your bottle brush plant as a shrub or as a full bottle brush tree, you’ll enjoy the bright spikes of color! And so will the local butterflies and bees.
Bottle Brush Tree Overview
|Common Name(s)||Bottle brush tree, bottle brush shrub, bottle brush plant, Mallee bottlebrush, prickly bottlebrush, scarlet bottlebrush, common red bottlebrush, common red bottle brush, crimson bottlebrush, lemon bottlebrush, green bottlebrush, Albany bottlebrush, narrow-leaved bottlebrush, pine-leaved bottlebrush, stiff bottlebrush, fibrebark, paperbark, lesser bottlebrush, tubada, gold-tipped bottlebrush, white bottlebrush, willow bottlebrush, weeping bottlebrush, creek bottlebrush|
|Scientific Name||Callistemon brachyandrus, Melaleuca brachyandra, Callistemon citrinus, Melaleuca citrina, Callistemon lanceolatus, Callistemon flavovirens, Melaleuca flavovirens, Callistemon glaucus, Melaleuca glauca, Callistemon speciosus, Callistemon linearis, Melaleuca linearis, Callistemon pinifolius, Callistemon rigidus, Callistemon nervosus, Melaleuca nervosa, Callistemon nervosum, Callistemon phoeniceus, Melaleuca phoenicea, Callistemon polandii, Melaleuca polandii, Callistemon salignus, Melaleuca salicina, Callistemon subulatus, Melaleuca subulata, Callistemon viminalis, Melaleuca viminalis|
|Height||Varies by species|
|Water||Drought-tolerant plant, water infrequently|
|Temperature||45-90 degrees Fahrenheit|
|Soil||Well-draining, low alkalinity|
|Fertilizer||Balanced 8-8-8 slow-release fertilizer in spring, summer, fall.|
|Propagation||By seed or cuttings|
|Pests||Sawfly larvae, scale, web moth (webbing caterpillar). Also susceptible to fungal diseases like root rot, stem disease, powdery mildew, and leaf spot.|
Types Of Bottle Brush Tree
As I mentioned above, there’s around 50 different species of bottle brush trees, and some confusion in the naming. I can’t cover them all today, but let’s go over a few of the best-known melaleucas and callistemons!
‘Melaleuca brachyandra’, ‘Callistemon brachyandrus’, ‘Mallee Bottlebrush’, ‘Prickly Bottlebrush’, ‘Scarlet Bottlebrush’
Callistemon brachyandrus. Source: Akos Kokai
Sharp-tipped leaves are the origin for the “prickly” name for this plant, and it definitely fits. Up to 2″ in length, these pointy leaves require the use of gloves to prune, but the flower stalks more than make up for the trouble.
Those flowers are actually clusters of 7-36 small flowers with extremely long stamens. The stamens are bright scarlet in color with yellowish-green tips, giving them a distinctly dual-colored look.
Visually stunning to look at, this plant can grow from five to thirty feet in height.
‘Melaleuca citrina’, ‘Callistemon citrinus’, ‘Callistemon lanceolatus’, ‘Common Red Bottlebrush’, ‘Crimson Bottlebrush’, ‘Lemon Bottlebrush’
Callistemon citrinus. Source: TCL 1961
One of the very first Australian plants to be taken out of the country in the 1770’s, the lemon bottlebrush is a popular variety. It produces a profusion of brilliant crimson flower stalks that bloom year-round, washing across the plant in a fiery wave.
Some cultivars produce vivid pink or white stalks as well.
Grown quite often as a tree, melaleuca citrina gets its citrus-related names from the scent of the leaves when crushed. This scent is quite similar to various kinds of citrus leaves and is quite pleasant.
The leaves also tend to produce oils, allowing the fragrance to linger around the plant on warm summer evenings.
This bottle brush tree has a shrubbing habit, tending to stay in the 3-10′ range. It’s often used to create brightly-colored hedges. However, it can be trained to full tree growth as well.
‘Melaleuca flavovirens’, ‘Callistemon flavovirens’, ‘Green Bottlebrush’
Callistemon flavovirens. Source: Michael Jefferies
Another bottle brush tree that stays towards the smaller side, the green bottlebrush averages a 3-10′ height.
This plant sends out flowers from May through December in shades which range from a pale green to a cream or white color. Each is tipped with light yellow, giving that multilayered coloration that bottlebrush plants are known for.
New leaf growth is silvery, but darkens to a medium green tone against the dark, woody bark. Unlike some of the other bottle brush varieties, this plant produces egg-shaped leaves with the narrower part of the egg towards the stem.
‘Melaleuca glauca’, ‘Callistemon glaucus’, ‘Callistemon speciosus’, ‘Albany Bottlebrush’
Callistemon glaucus. Source: Wildlife Travel
Widely grown as an ornamental, callistemon glaucus tends to stay in the shrubby growth pattern of up to 10′ in height. Its leaves tend towards a lighter green with a bluish tinge to them, and are long and slender with a slightly ovoid shape.
The flower stalks for the Albany bottlebrush tend to stay in the bright red or deep red-pink range, tipped with tiny pale yellow specks.
‘Melaleuca linearis’, ‘Callistemon linearis’, ‘Callistemon pinifolius’, ‘Callistemon rigidus’, ‘Narrow-Leaved Bottlebrush’, ‘Pine-Leaved Bottlebrush’, ‘Stiff Bottlebrush’
Callistemon linearis. Source: Maggi_94
As you can tell, this plant has had quite a number of botanical names over time. In part, that’s due to the confusion of particular cultivar names with the botanical name.
The base species has leaves which are linear in shape and about a half inch wide, where the other cultivars vary in their leaf shapes slightly.
Producing vibrant red spikes of color, the narrow-leaved bottlebrush is a good choice for people in damper or swampier locales. It is widely cultivated, but is most often seen in roadside plantings rather than garden environments.
‘Melaleuca nervosa’, ‘Callistemon nervosus’, ‘Callistemon nervosum’, ‘Fibrebark’, ‘Paperbark’
Callistemon nervosus. Source: Arthur Chapman
Fibrous, papery bark from this plant was used widely by aboriginal Australians for carrying containers or padding. The oil-producing leaves were used as a decongestant, but also used in a similar way as the related tea tree plant (Melaleuca alternifolia).
With blooms in either a creamy white or a rich, dark red, fibrebark is a popular bottle brush tree to grow. It’s a distinctly tree-type plant, growing from seven to fifty feet in height.
The layered bark makes an interesting element in landscaping, and the blooms appear from April to September.
‘Melaleuca phoenicea’, ‘Callistemon phoeniceus’, ‘Scarlet Bottlebrush’, ‘Lesser Bottlebrush’, ‘Tubada’
Callistemon phoeniceus. Source: Rob Young
With a height that can soar to up to 20 feet, this bottle brush tree can be grown as either a tree or a shrub. The lesser bottlebrush is capable of growing in a number of soil types although it prefers sandier soil, and tends to transition well to unusual climates.
Spires of pinkish-red or purplish-red flowers rest above lateral blue-green leaves and rough bark. Flowering tends to be heaviest from October through January in its Australian natural habitat, but can happen at other times of year.
‘Melaleuca polandii’, ‘Callistemon polandii’, ‘Gold-Tipped Bottlebrush’
Callistemon polandii. Source: Arthur Chapman
A hardy shrub that can grow to 10′, the gold-tipped bottlebrush is widely grown in warm coastal areas. It’s one of the varieties that has transitioned extremely well to California growing, particularly in southern or central areas of the state.
This bottle brush plant is widely used as a hedge or shrub plant, as it tends to fill out extremely well. However, it’s known to damage wastewater pipes, so avoid planting this near buried water or sewer pipes.
‘Melaleuca salicina’, ‘Callistemon salignus’, ‘White Bottlebrush’, ‘Willow Bottlebrush’
Callistemon salignus. Source: Tatiana12
Popularly seen as a streetside tree or shade tree in a park, the white bottle brush tree can grow to heights of up to 50 feet. Its papery bark and white flowers are a popular landscape addition.
Cultivated forms can have pink or red flower stalks as well, but it’s known for its white blooms.
Its leaves have a resemblance to those of some willow species, spawning one of its common names and the reference to salix in the botanical name. The creamy white flowers tend to be a food source and draw birds of multiple types.
‘Melaleuca subulata’, ‘Callistemon subulatus’
Callistemon subulatus. Source: Eric Hunt
For people in more northern reaches of California and up the west coast of the United States, considering callistemon subulatus is one of their best bets. This bottle brush shrub grows 3-7′ tall and makes an excellent hedge plant, producing flowers through most of the summer months.
Hardy in many environments, this plant can tolerate cooler temperatures or extremely hot ones, provided that it has some shade. It also does fairly well with sea air, and is a popular plant in and around San Francisco.
‘Melaleuca viminalis’, ‘Callistemon viminalis’, ‘Weeping Bottlebrush’, ‘Creek Bottlebrush’
Callistemon viminalis. Source: Ahmad Fuad Morad
Last on the list, but definitely not least, is the weeping bottle brush. Possibly the most cultivated of the bottle brush plants in garden settings, this is absolutely the most popular variety on today’s list!
Raised either as a shrub or as a multi-trunked tree that can reach heights of 30 feet, the weeping bottlebrush provides food for nectar-consuming wildlife.
Its dense root system is used to reinforce riverbanks, as the roots mat together and help to prevent erosion.
Callistemon viminalis is not frost-hardy, and has issues with salt spray. However, it can be grown in most environments if protected from cold or sea air. This plant has become popular around the world for its brilliant red profusion of flowers.
Bottle Brush Tree Care
Once established, care is super-simple: water it when the soil starts to dry out, and give it some fertilizer at regular intervals. Young plants require a little more preparation, though.
Read on to find out the best way to prepare your bed and care for your bottle brush tree!
A red-flowered melaleuca nervosa. Source: Arthur Chapman
Before you plant your bottle brush plant, it’s important to be sure your sun conditions are going to be right.
First, consider your bottle brush tree species. The vast majority of them prefer full sun, but there are a few of the shrubbing types which can tolerate partial shade.
Second, make sure that sun will reach that spot in the winter. A south-facing placement usually ensures you should have adequate sunlight for most callistemons all year.
As bottle brush plants do well in zones 9-11 normally, they tend to have good resistance to too much heat. They won’t like the cold, however. Some varieties can take low temperatures, but they are not able to handle repeated frost conditions.
If you live in a location where you get snow or extremely cold conditions during the winter, you should keep your bottle brush tree in a shrubbery-type growth type and plant it in a container. That way, you can optimize placement for light, and it can be brought indoors with a grow light for the winter months.
Older bottle brush trees which have gained significant growth can tolerate cold weather better than those which are young.
The average bottle brush is going to prefer regular watering, but it won’t necessarily require daily watering as these plants tend to be somewhat drought-resistant.
Depending on its specific species, age or size, watering requirements vary widely. However, a good rule of thumb during the first year or two is to check the top four inches of soil at the base of the plant. If it is damp, you’re giving it enough water. If it’s powdery and dry, it needs watering.
To develop a good root system, I recommend slow, deep watering patterns. Using a drip system or soaker hose will provide these conditions and help encourage the root mass to expand as necessary.
Established plants that are more than two years old are much more drought-resistant than younger plants. These have had plenty of time to establish a good root system. Water older bottle brush trees during prolonged dry periods or when trying to stimulate flowering.
You’re welcome to water more often, as long as the soil drains really well. However, be careful not to overwater!
Bottle brush trees can withstand short periods of flooding, but try to avoid standing water once floodwaters recede.
Melaleuca nervosa bark, also known as paperbark. Source: Arthur Chapman
Bottle brush trees grow well in a wide variety of soil conditions. In the wild, they often grow along creek beds or in sandier soils, but some species do extremely well in clay as well. Some species have extensive matting root systems that can help prevent erosion, even with sandier soil.
Still, one thing which should always be avoided is highly alkaline soil.
Too much alkalinity will cause bottle brush trees to suffer yellowing of their leaves from chlorophyll loss. If leaves remain yellow for too long, the plant will die off as it can’t process sunlight properly.
For overall best results, go for a pH range between 5.5 and 7. Work in some compost to add nutrients, and perlite to slightly loosen clay-type soils. If you have sandier soil naturally, skip the perlite and simply work in compost.
Your overall goal is to have a soil which the roots can easily permeate and which remains damp, but not wet. Application of a few inches of mulch around the base of your plant will help keep the soil moist.
A closeup of a Callistemon glaucus flower. Source: caz15x
I like to use a balanced, slow-release fertilizer for my bottle brush shrub. Applied evenly at the beginning of the spring, summer, and fall, an 8-8-8 slow-release fertilizer will encourage steady growth and flowering.
You don’t need to fertilize in the winter, as the plant simply won’t need added nutrition then.
A little extra phosphorous can help stimulate flower production in the right season and at the right time. The problem is that it needs to be applied a few weeks before normal flowering begins.
If you’re not sure when flowering should happen for your plant, it’s best to stick with a balanced fertilizer.
Propagation From Cuttings
It’s extremely easy to start your bottle brush tree from either seed or cuttings.
For cuttings, you want to take 6-inch cuttings from semi-matured wood. The best time to do this is during the summer. Use sterilized pruners to take the cutting.
Once you have your cutting, pinch off any lower leaves on the stem and any flower buds. Dip your cutting into a rooting hormone powder and then put it into your growth medium. You can use perlite, potting soil, or a number of other starters as growing medium.
Make sure the medium is damp, and then cover the cutting with a plastic bag to help keep moisture inside. You can base-water by setting your potted cutting into a tray of water if necessary, but avoid overwatering.
Wait for the cutting to take root, which should happen within 9-10 weeks, then remove the bag and acclimate your plant to the lower humidity before repotting.
Propagation From Seed
A closeup of seed pods from callistemon linearis. Source: John Tann
If you have seed, it’s simple enough to plant, but it will take a bit longer for your plant to become hardened to the weather. To give it the best chance, sow your seed during the springtime in a balanced potting mix.
As bottle brush plant seeds are extremely tiny, they will resemble dust. This means you’re likely to sow them rather heavily, but that’s okay. Thin down excess plants and keep the strongest specimens as they appear. Try to leave a few inches of space between plants.
Once they’re at least 6-8 inches in size, you can gently separate them and repot them.
Keep in mind that if you are growing different varieties of bottlebrush plants, they hybridize easily. The best way to keep the same features as the parent plant is to take cuttings.
If you’re only growing one variety, the seeds should produce true clones of their parent plant in most cases.
Transplanting your bottle brush requires some preparation of the soil. Read the “soil” segment above for more information.
For older bottlebrush trees, you will want to prepare a hole based on the size of the current plant roots. If the roots have a foot and a half spread, for instance, you want to prepare a hole that’s at least two feet deep and three feet across at the topmost point.
Preparing the soil in advance loosens it and makes it easier for the roots to spread out in. As much of the root mass will be a tangled mat near the surface, you need to ensure that there’s plenty of room for those roots to adapt to!
Young plants need a smaller prepared space. A good rule of thumb is double the root mass in width, and at least 1.5 times the root mass deep. This gives plenty of good aeration.
Potted bottle brush shrubs should be given 3-6 extra inches of space in their pot when transplanting to a new pot.
This Callistemon linearis has been trained in an espalier style. Source: wallygrom
There are two types of pruning which are commonly done for bottlebrush shrubs or trees: tip pruning, or flower pruning.
Tip pruning should be done when the new growth is still extremely young, and before it’s had the chance for the stem to harden in any way.
As flowers will grow from these tips, you may sacrifice some flowers if you prune the stems too late. However, this will help you shape the plant if necessary.
Flower pruning is done just as the flowers are beginning to fade. Neatly snip off the flower just behind the lowest set of blossoms, leaving as much stem intact as you can. This may spur additional flower growth from the same stem.
You can prune to train your bottle brush plant to a specific growth pattern. Bottle brush trees also work well for the traditional practice of espalier, or training against a wall or building.
The seed pod on the left is nearly ready to harvest. The one on the right isn’t dry yet. Source: John Tann
If you want to gather seed from your bottlebrush tree, be sure to leave the flowers intact even after they’ve faded. That flower stalk is where the seed pods grow.
Pollinated flower stalks will form seed heads filled with multiple seed pods. Initially, these will be greenish, but over time they will dry to a dark, hardened brown.
As they start reaching the brown and hardened stage, place a paper bag over the top and rubberband it in place beneath the seedhead securely. Wait for a bit longer, and then cut off the stem below the seedhead and leave it to completely dry out.
The seed pods will open on their own as long as they’re kept in a warm, dry place, and a good shake will release the seed into the paper bag.
Scale insect damage on bottle brush tree. Source: Doug Beckers
The majority of your problems will arise from overwatering. But there are a few pests which can attack your bottle brush. Let’s go through the possible issues that might arise and how to deal with them.
Winter’s chill can cause leaf browning on your bottle brush tree. But do not panic! As long as the branches themselves are not dead, it can recover.
If you’ve had a sudden cold snap, consider wrapping plastic or burlap around your plants to keep them a little warmer.
Be sure to leave ventilation at the top and underside of the plant so you don’t develop powdery mildew or leaf spot. Remove it as soon as the weather warms back up.
There are a few pests that attack bottle brush: sawfly larvae, scale, and the web moth (also referred to as the webbing caterpillar).
The sawfly itself will not harm your plants, but their larvae assuredly will. These sawfly larvae cause skeletonization of leaves and defoliation.
You can eliminate the larvae with a number of products including neem oil or a more potent azadirachtin spray like AzaMax. Also consider spinosad sprays like Monterey Garden Insect Spray, or even dusting the plant with diatomaceous earth.
Scale insects are a bit more irritating, as they can be hard to spot hidden on the underside of leaves. These cause pale trails to form through your bottle brush leaves.
For small infestations, you can carefully scrape the scale off, or blast it off with hard sprays of water. Larger infestations respond well to the use of neem oil or AzaMax.
Finally, the most destructive pest to bottle brush shrubs is the web moth, also known as the webbing caterpillar. These pests will attack younger foliage, webbing it together to form a cocoon. They can defoliate plants quickly, and one of their favorite targets is the bottle brush.
If you see any branches or leaves pulled together to form a cocoon, or dust that looks like sawdust near a web-coated section of branch, remove it immediately and dispose of it. This should remove the web moth larvae.
While I don’t know if it’s been tested against webbing caterpillars, bacillus thurigiensis (also known as BT) should help destroy these larvae. It’s certainly worth the effort!
Use a product such as Monterey BT if you wish to see if the bacillus will deal with your caterpillar problem, being sure to thoroughly soak through any cocoons to hit the webbing caterpillars within.
I really dislike suggesting inorganic methods to combat a pest. However, if you do not trim off visible cocoons and the BT doesn’t work, you may have to resort to the use of a carbaryl insecticide such as Sevin. This is known to be extremely effective against web moth larvae.
Root rot can affect bottle brush trees if the soil is consistently too wet. This soggy soil promotes the growth of fungi that cause the root rot. It can cause yellowing of leaves, discoloration of the trunk, dying back of branches, and can lead to plant death.
To avoid this, water your bottle brush plant only when it needs it, and water slowly but deeply to allow water to penetrate the soil and drain off well. If necessary, apply a copper-based fungicide such as Bonide Copper Fungicide as a soil drench to try to kill off the fungal growth.
Another disease, stem disease, develops also from overwatering. Stem disease is a bacterial issue that also enters at the roots but travels to the branches. It causes stunted, thin branch growth and can slowly kill your plant.
Ensuring your plant has full sun will help water evaporate from the soil more quickly, but the easiest way to avoid this is to simply not overwater. Treatment is withholding water until the soil is dry, then only water enough to just barely dampen the soil.
Limit the plant’s exposure to water until it recovers from the bacterial infection, and prune damaged branches. Be sure to sterilize your pruners to avoid cross-contamination.
Powdery mildew is caused by dampness on leaves where yet another fungus can develop. This one, at least, is relatively easy to treat! Spray all plant surfaces, both tops and bottoms, with neem oil. Retreat every few days until the powdery mildew is gone.
Leaf spot is the final fungal growth that can become a problem.
While a few spotted leaves won’t harm anything, if the fungal growth spreads throughout the plant’s leaves it can cause plant death. Avoid watering the foliage, which is where the fungi develops if it remains wet for too long. Ensure the plant has plenty of airflow around it to keep leaves dry.
Ready to benefit from the bounty of beneficial pollinators that your bottle brush bush will bring? (Boy, that’s a lot of B-words!) In all honesty, these white, pink, or red bottle brush trees are beautiful additions to your landscaping, and they’re surprisingly easy to take care of once established. What’s your favorite shade of bottle brush tree? Tell me below!
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