Bottlebrush tree or Callistemon citrinus. is an evergreen shrub named for the spikes of the flowers that grow at the end of the branches, with a close resemblance to a bottle brush.
They can tolerate humidity and can be grown as shrubs or trees that can get 15 feet tall—most varieties of bottlebrush bloom with flowers in shades of red and crimson.
The bottlebrush tree is a summer plant native to Australia. It blooms throughout the summer season with cylindrical-shaped flower spikes that are 6 to 10 cm in length and 4 to 7 cm in diameter.
The bottlebrush tree fills your garden with a delicious lemony citrus smell.
It is an exotic plant with bright fluffy flowers and foliage to give a unique touch to your home garden.
With its vibrant red-coloured flowers, it attracts hummingbirds, butterflies, bees, and other wildlife.
It is an adaptable plant that can be planted anywhere in your lawn, against a wall or fence, even in large pots to add a decorative touch and serve as a centrepiece.
In this article, we will guide you about the bottlebrush tree planting and care to help you maintain and grow this colourful summer plant in your garden.
- 1 Bottlebrush Tree Care
- 2 HOW TO TAKE CARE OF BOTTLEBRUSH TREE
- 3 PEST AND DISEASES
- 4 FREQUENTLY ASKED QUESTIONS
- 5 CONCLUSION
Bottlebrush Tree Care
The main soil requirement for a bottlebrush tree is good drainage.
Any soil will work well for a bottlebrush tree, but it loves soil with pH ranging between 5.5 and 7. If the soil is very poor in quality, you can add compost for nutrients to amend it before planting.
Prepare the fertile soil with peat and sand to improve the drainage. Making the soil ready beforehand loosens it, which makes it a lot easier for the roots to spread.
The ideal soil is where the roots can easily permeate, and it remains damp, not wet. Avoid soggy soil or areas where water can gather.
As a native Australian plant, the bottlebrush prefers warm temperatures.
Bottlebrush requires a very mild climate for growth. The ideal temperature for growth is 50°F – 90°F (10°C to 32°C).
If you live in a harsh climate area, you can plant them in pots to protect them in harsh conditions. If you are planting a bottlebrush indoors, maintain a room temperature of 15 degrees Celsius.
Bottlebrush trees are sun-lovers, so they require full sun to thrive.
Grow them in a sunny spot as the plant needs plenty of sunlight to produce beautiful red flowers.
For planting a bottlebrush directly in the ground, choose a place where the plant receives at least six hours of sun in a day.
A south facing position makes sure the bottlebrush tree gets adequate sunlight throughout the year.
Check the neighbouring plants to make sure you don’t plant the bottlebrush in a crowded area or where plants might grow bigger, leading to blocking the sunlight.
Bottlebrush trees growing in containers also need to be positioned in a sunny spot and can be easily moved around to encourage plant growth and blooming.
If you live in cold areas, consider planting it indoors in a container. Once the plant is established, you can transplant it to the outdoor garden.
HOW TO TAKE CARE OF BOTTLEBRUSH TREE
The bottlebrush tree is an excellent garden plant. If you want to transplant your indoor bottlebrush tree, dig a hole based on the size of the plant roots.
The hole should be double the size of the roots in width and at least 1.5 times depth to provide good air circulation. Tease the roots of the plant slightly and place it in the hole.
When planting in groups, leave at least two feet spacing between each plant.
Growing and caring for the bottlebrush is simple and easy. Once developed, a bottlebrush can tolerate drought and harsh conditions. But you need to take care of your plant for healthy growth and blooming.
Moderately water this tropical plant when it is young; Plants that are two or more years older are more drought-resistant as compared to young plants.
Laying mulch on the soil will facilitate water-retention and prevent weeds.
Use a 2-inch (5 cm.) layer of shredded hardwood or bark or a 3- to 4-inch (8-10 cm.) layer of light mulch such as pine straw, hay or shredded leaves.
Like any other garden plant, do not overwater the bottlebrush to prevent root rot.
In the absence of rainfall, water the plant every week during the growing season. Water the plant daily during the first week after planting; water slowly to ensure the water is absorbed deeply in the soil to develop a robust root system.
If you are growing your plant in a container, take special care to avoid overwatering as the water drainage is less in the container compared to the ground soil.
You can add builders sand to the soil mix in the container to improve the drainage.
Frequently inspect the top 4 inches of the soil; if the soil is slightly damp, the plant is well-watered, and if its dry and powdery, your bottlebrush tree needs water.
The Bottlebrush tree should be fertilized for the first time with 2-inches compost in their second spring after planting. During warm months feed the plant with low-phosphorus fertilizer every month.
It will help the bottlebrush tree in growing plenty of flowers throughout the season. Phosphorus based fertilizer helps in flower development.
If your plant is struggling with blooming despite all the care and watering, you might be using the wrong fertilizer.
You can use a general-purpose fertilizer to encourage blooming for the bottlebrush tree or even an organic fertilizer such as compost or manure.
Use a granular fertilizer for the plant growing in the soil outdoors while a liquid fertilizer is recommended for plants in containers.
The bottlebrush tree is prone to fertilizer burns causing leaf discolouration.
Therefore use the amount indicated in instructions or if unsure use less than required.
Applied at the start of the spring, summer, and fall, an 8-8-8 or 10-10-10 slow-release fertilizer will enable steady growth and flowering.
Add fertilizer once a year until the plant is fully grown.
This plant does not grow in cold months; avoid fertilizing during those months as the extra nutrients are not required.
Read our full plant nutrients and fertilizer guide here.
If you intend to propagate the bottlebrush tree, you can do this with seeds or stem cuttings.
Propagate the bottlebrush tree by seeds
- To collect bottlebrush seeds, locate the fruits growing along the flower stems in clusters.
- Carefully remove the fruit from the plant and store them in a cool, dry place in a paper bag.
- When the fruits open, you can collect the tiny seeds and sow them in moist soil during the spring season.
After the seedlings appear, transfer them to bigger pots for growth and continue the usual bottlebrush care.
Propagate the bottlebrush tree by stem cuttings
Propagation by stem cuttings is done in summer.
- Cut the stems from semi-mature wood using sterilized pruners. Remove any leaves or flower buds from the cuttings and dip them in a rooting hormone powder.
- Now place the cuttings in a growing medium(perlite, potting soil, or any other starters).
- Ensure that the medium is damp by covering the cutting with a plastic bag to retain moisture. When the roots appear after 9 to 10 weeks, remove the plastic bag and replant the bottlebrush tree outdoors.
For most plants, pruning diverts the plant’s energy into flower production.
Pruning is necessary for the excellent health of the plant. Knowing how and when to prune is essential for bottlebrush tree care.
The bottlebrush tree needs light pruning to keep it under control.
The time of the year you choose to pruning the bottlebrush tree will directly impact the growth and blooming; continuous pruning leads to a lack of flowers in the preceding year.
You should remove the inner branches if they are damaged or diseased, whereas thin them lightly if the interior growth is turning brown due to lack of sunlight. It will ensure proper sunlight is reaching the inner branches of the plant.
- You should prune the bottlebrush when the flowers fade to avoid damaging the future blooms.
- Keep the pruning minimal by clipping a few inches(5cm) below the tips.
- If you are pruning the plant to maintain size and shape, prune each stem individually by cutting each branch just above a node.
The simple rule is that pruning for size or shape should be done in early spring, whereas pruning for health and maintenance should be done twice a year, both in early spring and late summer.
PEST AND DISEASES
bottlebrush tree is cherished for its bright flowers and evergreen foliage.
Like other garden plants, a bottlebrush is also prone to certain diseases and pests.
Some of the diseases are easily treatable, while others are severe diseases that are difficult or sometimes impossible to treat.
Knowing the symptoms and treatments is necessary for disease prevention and plant care. The following are the most common diseases and pests for bottlebrush tree:
It is a fungal disease caused by excessive watering. Overly wet soil and foliage lead to new twigs growth on the tree, and the branches bloat.
You will have to cut the unhealthy twigs growing on the bottlebrush tree and dispose of them. You also need to alter watering habits to avoid excessively moist soil.
Water the plants only when necessary and consider adding sand to help with drainage.
This bottlebrush disease is also caused by water on the foliage.
If you notice white or grey covering anywhere on the plants, it most probably indicates powdery mildew. In some cases, it can turn the leaves brown or yellow.
You can spray the plant with fungicide spray or neem oil to treat powdery mildew. You can also consider watering the plant from below instead of top to prevent this disease in the future.
Avoid planting the bottlebrush in dark or damp corners and water the plants in the morning so that the leaves can dry throughout the day.
Fungus and overwatering the soil causes root rot. You will notice the tree is dying; the trunk is turning odd colours, the leaves are yellowing and falling.
The root rot fungus can attack the neighbouring plants as well.
Make sure the soil is well-drained to prevent overly moist soil. Apply the fungicides to treat root rot. Gardeners recommend proper care to avoid this disease as curing is difficult.
The best protection against root rot is prevention by controlling the water given to the plant.
It is caused by the fungus living in the soil. The prominent symptoms of this disease are yellowing flowers and dying branches.
Verticillium wilt does not kill the bottlebrush tree, but it is difficult to remove this fungus from the soil.
This disease is difficult to identify as the symptoms are similar to other pests and diseases.
Cut the stem, and if you notice any dark circles on the cross-section, your bottlebrush tree is suffering from verticillium wilt. Treat the plant with fungicides and replant the tree in another location.
This is a fungal disease that affects the beauty and appearance of the tree.
It spreads due to soggy or overly sweet soil. Premature defoliation and spots on the leaves are the prominent symptoms of leaf blotch or spotting.
The spots are brown with yellowish border and increase in size over time. To prevent the fungus from reattacking, burn the infected leaves, and spray the tree with liquid copper fungicide.
This is also a fungal disease that spreads rapidly and affects the growth of the bottlebrush tree. It is caused by improper fertilization and wet soil.
The tree becomes disfigured, lifeless, and the branches become uneven with swollen areas. Proper fertilization and fungicide sprays can protect the bottlebrush tree from this deadly disease.
It causes skeletonization of leaves and defoliation. These larvae are removed by using neem oil or a strong azadirachtin spray. You can even dust the plant with diatomaceous earth.
They are hard to spot and cause pale trails on the bottlebrush leaves. You can scrape the insects off the leaves or use pressurized water sprays to remove them. For massive infections, you have to use neem oil or other powerful sprays.
Web moths or webbing caterpillars are the most damaging pest for bottlebrush trees. They attack young leaves by webbing them together to form cocoons.
If you notice any cocoons or sawdust on the branches or leaves, immediately remove and dispose of them. You can also use carbaryl insecticide, which is proved to be very effective against web moth larvae.
Inspect your bottlebrush tree regularly for diseases and pests.
In addition to the diseases and pests, the bottlebrush is also affected by severe climatic conditions.
Harsh winter conditions affect the bottlebrush as they can cause leaf browning, but if the stems are not dead, your bottlebrush tree can recover.
Wrap the bottlebrush tree with plastic or burlap to keep it warm in harsh cold weather.
Ensure proper air circulation on the top and underside of the plant to avoid any diseases due to prolonged dampness.
FREQUENTLY ASKED QUESTIONS
Why is my bottlebrush tree not blooming?
Bottlebrush tree grows bright red flowers to beautify and brighten up your garden. But if the flowers are not blooming, you are probably doing something wrong while caring for your plant. Consider the following:
- Sunshine: Bottlebrush thrives in full sun. Make sure your plant gets sunlight for at least 6 hours. The neighbouring plants can also block the sunshine. You can cut the nearby shrubs or consider replanting in a new position to ensure proper sunlight.
- Fertilizer: Nitrogen fertilizer causes foliage but sometimes reduces the growth of flowers or fruits. If you are using nitrogen fertilizer, read and follow the instruction on the plant label and fertilizer carefully.
- Pruning: It encourages blooming and keeps the plant in shape, but if you are pruning the bottlebrush at the wrong time, it might have the opposite effect. Pruning the plant when it’s loaded with buds will reduce the number of flowers and can even lead to no blooming. The best time to prune your bottlebrush is right after flowering in late spring and summer.
Why are the leaves of bottlebrush drying?
There could be several causes for drying or dead leaves. Most of the time the plant is still treatable; consider the following reasons for drying leaves:
- Wind and extreme cold can damage the leaf, causing them to dry, turn brown, or dieback. Plant the bottlebrush in an area with wind protection else the wind will cause extreme dryness and the water to evaporate quickly. The bottle brush is damaged when the temperature drops below -6 degrees Celcius. In this case, remove the damaged leaves by pruning the stems.
- Iron deficiency causes the bottlebrush leaves to turn yellow and restricts the growth leading to dry and dead leaves. Iron deficiency is caused by compacted and improper watering. Applying iron chelate to nearby soil will solve this problem.
- Armoured scale, a bottlebrush pest can also cause dry, dead leaves. They feed on the sap in the leaves and stem. For a small infection, prune the infested branches. For severe infections, place sticky traps on affected branches and spray the leaves with ready-to-use horticultural oil spray. Inspect the plant and continue the treatment for ten days to completely get rid of the pests.
How often should I water the bottlebrush tree?
You should water the bottlebrush tree every day during the first week after planting. Water the plant slowly so that the roots are thoroughly saturated. Later on, reduce the watering to two or three times a week. Eventually, stop regular watering and water the plant only when the soil feels dry.
How to protect my bottlebrush tree against tree suckers?
Plant or tree suckers are an effort by the plant to grow more branches. It is preferable to prevent tree suckers than to remove them.
You can control tree suckers by keeping the plant in good health; avoid additional stress on the plant caused by drought, overwatering, diseases, or pests.
Regularly prune the bottlebrush, but avoid over-pruning as it can stimulate tree suckers.
If you notice any tree suckers, remove them immediately as they will divert the energy from healthier branches. Use a clean pair of pruning shears and cut the sucker close to the tree. Leave the collar to help with recovery.
Bottlebrush is a flowering perennial desert shrub that can be grown in a range of varying sizes and shapes. This ornamental plant requires minimum maintenance; it is a perfect choice to be grown as a shrub in your home garden or a small tree to decorate your entryway or patio.
Once the bottle brush tree is fully grown, it does not require any special attention and is easy to care for.
With lots of sun and a little fertilizer, the bottle brush plant will reward you by adding vibrant colour and texture to your home garden.
Marcel runs the place around here. He has a deep passion for houseplants & gardening and is constantly on the lookout for yet another special plant to add to his arsenal of houseplants, succulents & cacti.
Marcel is also the founder of Iseli International Commerce, a sole proprietorship company that publishes a variety of websites and online magazines.