Callistemon are tender evergreen shrubs with aromatic, linear to lance-shaped leaves and long round brush-like flower spikes. Loved by bees and butterflies.
Botanical Name: Callistemon (ka-lee-stay-mon)
Common Names: Bottle Brush
Foliage: Evergreen, mid to dark green, narrow lanceolate leaves.
Flowers: Long terminal flower spikes, where the coloured stamens stick out radially like the bristles of a bottle brush. Available in shades of red, pink or white. The flowers are followed by woody seed capsules.
Flowering Period: Summer.
Soil: Moist but well-drained soil (clay, sand or loam). Acid to neutral pH.
Conditions: Full sun. Plant in a west or south facing aspect, in a sheltered position.
Habit: Bushy, lax.
Type: Small tree or shrub.
Hardiness: Tender - protect from frost. Can be grown outside in coastal and mild regions of the UK (down to about -5°C).
Grow in a sheltered position in full sun, in a moist but well-drained soil. They grow well in quite dry areas so long as the sub soil is moisture retentive.
In the wild Callistemon is a vigorous grower, reaching heights of around 3m (10ft) or more. Container grown plants should remain more compact.
Small tender forms can be grown successfully in containers and brought into a cool conservatory or greenhouse over winter. Hardier forms can be grown outside in milder areas, although it is advisable to give them the protection south-facing wall.
Flowering stems are sought after by flower arrangers.
Pruning is not necessary except to keep plant tidy and remove any dead or damaged wood. If the flower spikes are left on, new growth will spurt from the ends.
Can be affected by red spider mite, mealybugs and scale insects under glass. Generally disease free.
Increase from seed sown under glass in spring. Alternatively take semi-hardwood cuttings taken in summer and root in a propagator.
Callistemon citrinus is one of the hardiest forms with a bright crimson flower spikes, about 4in (10cm) long. The leaves emit a lemon fragrance when crushed. Height and spread up to 5ft (1.5m). For sale at You Garden. The cultivar, 'Splendens' is one of the most colourful with bright crimson brush-like flower spikes. 'Anzac White' bears luscious white flowers from spring through to early summer. For sale at Suttons.
Callistemon laevis (crimson bottlebrush) bears lemon-scented leaves and dazzling crimson-red flowers. For sale at Crocus.
Callistemon linearis (RHS award-winning) is a bushy, medium-sized evergreen shrub with linear leaves and masses of vibrant fiery red bottlebrush flowers in summer. Height to 10ft (3m), spread to 13ft (4m). For sale at Suttons.
Callistemon 'Masotti Mini Red' is a good compact variety with good drought tolerance. Perfect for container growing. For sale at Thompson & Morgan.
Callistemon rigidus has bright red flowers.
Callistemon salignus is reasonably hardy with 3in (7cm) long cream or pink flower spikes.
Callistemon sibieri (Alpine Bottle Brush) is a fairly hardy form with small yellow flower spikes.
Callistemon viminalis (Weeping Bottle Brush) produces a small evergreen tree with scarlet flowers. Height to 20ft (6m). Cultivar 'Hot Pink' bears bright pink flowers in early summer. For sale at Van Meuwen.