Gardeners in the Coastal and Tropical South love the fast-growing bottlebrush for its colorful flowers carried in dense spikes or round clusters with long, bristle-like stamens, hence the name bottlebrush. Hummingbirds love the flowers, too, which are followed by woody capsules that can last for years and may resemble rows of beads pressed into bark.
I. Appearance and Characteristics
Melaleuca citrina, the common red bottlebrush, crimson bottlebrush, or lemon bottlebrush, is a plant in the myrtle family Myrtaceae, and is endemic to eastern Australia. Some Australian state herbaria continue to use the name Callistemon citrinus. It is a hardy and adaptable species, common in its natural habitat. It is widely cultivated, not only in Australia. It was one of the first Australian plants to be grown outside the country, having been taken to England in 1770 by Joseph Banks.
Melaleuca citrina is a shrub growing to 5 m (20 ft) tall but more usually in the range 1–3 m (3–10 ft) high and wide. It has hard, fibrous or papery bark and its young growth is usually covered with soft, silky hairs. Its leaves are arranged alternately and are 26–99 mm (1–4 in) long, 4–25 mm (0.2–1 in) wide, hard, flat, narrow egg-shaped with the narrower end near the base and with a pointed but not sharp end. There are between 7 and 26 branching veins clearly visible on both sides of the leaves and a large number of distinct oil glands visible on both surfaces of the leaves.
The flowers are red and arranged in spikes on the ends of branches that continue to grow after flowering and sometimes also in the upper leaf axils. The spikes are up to 45–70 mm (2–3 in) in diameter and 60–100 mm (2–4 in) long with up to 80 individual flowers. The petals are 3.9–5.8 mm (0.15–0.23 in) long and fall off as the flower ages. There are 30 to 45 stamens in each flower, with their “stalks” (the filaments) red and “tips” (the anthers) purple. Flowering occurs in most months of the year but mainly in November and December. Flowering is followed by fruit that are woody, cup-shaped capsules, 4.4–7 mm (0.2–0.3 in) long and about 7 mm (0.3 in) wide in cylindrical clusters along the stem. The fruiting capsules remain unopened until the plant, or the part bearing them dies.
M. citrina, as Callistemon citrinus had become established in cultivation in England by 1794 when flowering plants that were more than five years old had been observed at both Kew Gardens and Syon House and younger plants had become available in nurseries. It is widely cultivated, often as Callistemon citrinus and sometimes as Callistemon lanceolatus. It is easily propagated from seed or cuttings and grows in most soils, preferring a sunny location. It is frost hardy and responds well to watering and the application of fertiliser but is tolerant of drought and frost.
II. How to Grow and Care
Sunlight
Bottlebrush needs full sun, or at least six hours every day, to bloom. If planted in shade, or if crowded by taller plants that block the sun, consider moving the bottlebrush or trim back other tall plants, if possible. Bottlebrush puts on a colorful show in the garden and shorting it on sunshine will limit its beauty.
Watering
Bottlebrush needs minimal care. If the climate is dry or rainfall levels are low, supplement with good waterings to provide moisture for the first year as the root system becomes established.
Soil
Bottlebrush isn’t picky about the type of soil, but it needs to drain well. If it becomes water-logged, disease can set in. Conversely, if water can’t penetrate heavy soil, the roots won’t receive the deep water they need.
Fertilizing
Although not necessary if grown in a fairly fertile, loamy soil, an application of a low-phosphorus fertilizer in early spring and fall will be beneficial to these plants and may increase flowering. Feed with a balanced orchid fertilizer every 2 weeks.
Pruning
Very little routine pruning is needed—just remove any weak or dead branches after bloom or before spring growth. Don’t cut into bare wood beyond leaves; if you do, bottlebrush may not send out new growth. Bottlebrush blooms intermittently all year, so consider pruning after late spring or summer flowers. Remove suckers from the trunk periodically.
Propagation
Propagate Little John Bottle Brush using semi-hardwood cuttings.
- Select cuttings measuring 6″ to 12″ inches long.
- Cut the stem and dip the end in a hormone rooting powder.
- To propagate outdoors, prepare a section of soil by amending the existing soil with organic matter.
- Stick the cutting into the soil, ensuring several leaf nodes remain above the ground.
- When growing the plants indoors, use large pots filled with moist, well-drained soil.
- The cuttings should take root during the summer but shouldn’t be transplanted until spring the following year.
Pests and Diseases
Bottlebrush is not susceptible to pests. But root and crown-attacking fungus can be a problem if the soil is overly moist, as can twig gall. If new branch growth looks bloated, remove growth and allow the soil to dry. To prevent disease, make sure bottlebrush has good air circulation and keep the plant on the dry side.
III. Types of Bottlebrush
- Callistemon citrinus
Lemon Bottlebrush. Shrub or tree. Zones USDA 8-11. Most commonly grown bottlebrush; most tolerant of heat, cold, and poor soils. Massive shrub to 10–15 ft. tall and wide, but with staking and pruning in youth easily trained into narrowish, round-headed, 20- to 25-ft. tree. Nurseries offer it as a shrub, espalier, or tree. Narrow, three-in.-long leaves are coppery when new, maturing to vivid green. Bruised leaves smell lemony. Bright red, six-in.-long brushes appear in waves throughout the year. Variable plant when grown from seed; look for cutting-grown selections with good flower size and color, such as ‘Splendens’.
- C. Perth Pink
Shrub. Zones USDA 9-11. Dense, full growth to five to eight ft. tall and wide, with weeping branches and deep pink flowers to four inches long in spring and early summer. New growth is pink.
- C. rigidus
Stiff Bottlebrush. Rigid, sparse shrub or small tree to 15 ft. with 10-ft. spread. USDA 9-10. Sharp-pointed, gray-green (sometimes purplish) leaves to five inches long. Spring and summer red flower brushes are four inches long. Produces prominent seed capsules. The least graceful of the bottlebrushes.
- Melaleuca salicina
White Bottlebrush. Shrub or tree to 20–25 ft. tall, 10–15 ft. wide. USDA 8-11. Dense crown of foliage. Bright pink to copper new growth. Willow-like leaves two to three inches long. Pale yellow to cream-colored flowers appear in clusters in spring, and early summer. Train as a small shade tree or plant four to five ft. apart as a hedge.
- Callistemon sieberi
Alpine Bottlebrush. USDA 7-11. Shrub. To three to six ft. tall and wide, with a somewhat upright habit. Small, dark green leaves densely cover the branches. Cream to yellow flowers bloom from late spring to midsummer.
- Melaleuca viminalis
Weeping Bottlebrush. Shrub or small tree with pendulous branches. USDA 9-11. Fast growing to 20–30 ft. tall, with 15-ft. spread. Narrow, light green leaves and bright red, long brushes from late spring into summer; scattered bloom rest of year. Not for windy, dry areas. As a tree, it needs staking, and thinning to prevent tangled, top-heavy growth. Leaves tend to grow toward the ends of long, hanging branches.
IV. Uses and Benefits
- Ornamental uses
In warm regions, use the deer-resistant Little John Bottle Brush to bring winter interest to any landscape area.
The blue-green leaves and bright-red flowers stand out during the colder months.
Its versatile compact size allows it to grow as a low hedge or foundation plant.
In cool regions, grow Little John Dwarf Bottlebrush in three-gallon or larger containers.
Keep the plant outdoors during the summer and bring it indoors for the winter.
- Other uses
The herbicide Mesotrione was developed as a synthetic analogue of leptospermone, a natural herbicide produced by the roots of Callistemon citrinus.
Find Where to Buy the Best Crimson Bottlebrush (Melaleuca citrina)
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