Leptospermum GRANDIFLORUM

Leptospermum GRANDIFLORUM - Autumn tea tree, large-flowered tea tree, Leptospermum grandiflorum.

Can be grown in bonsai style!

Leptospermum, or tea tree, is a genus of evergreen shrubs and small trees in the myrtle family (Myrtaceae), comprising about eighty-five species. The vast majority of them are endemic to Australia, with several species originating from New Zealand and Southeast Asia, where the plants inhabit heaths, sandy plains, rocky slopes, and watercourse banks.

The shrubs branch densely; the bark on old branches is rough, often peeling in strips. The leaves are small, stiff, sessile or on a very short petiole, containing essential oils and emitting a pleasant fragrance when crushed.

The flowers are five-petaled, resembling small stars or wild rose blossoms, white, pink, or red, borne singly in leaf axils and profusely covering the shoots. The fruit is a dry woody capsule opening by valves, containing numerous very small seeds.

Leptospermum grandiflorum is a species endemic to eastern Tasmania, where it grows along rocky slopes and stream banks. It is a densely branched shrub or small tree usually 1.5-5 m (4.9-16.4 ft) in height, with rough bark on mature branches and whitish young shoots.

The leaves are thick, grayish-green, elliptic or broadly ovate, 10-15 mm (0.4-0.6 in) long and 4-8 mm (0.16-0.31 in) wide, tapering to a short, often twisted petiole. The flowers are large for the genus, about 20 mm (0.8 in) across, with five white, rarely pinkish petals. Blooming occurs in summer and autumn.

Leptospermum seeds are exceptionally tiny, almost dust-like - which is precisely how the genus received its name. Soaking them is impractical: such fine seeds are easily lost in liquid and damaged, so the substrate itself is disinfected: before sowing, it is drenched with a weak solution of potassium permanganate and dried. Scarification and stratification are not required.

Sowing is conducted on the surface over a moistened acidic substrate without lime, with the addition of sand or perlite - the seeds are only lightly pressed onto the surface without burying. The sowing is moistened with a spray bottle using a growth stimulant solution: SUPERthrive, HB-101, Aminozol, Epin, or Zircon, covered with film or placed in a propagator, and germinated in light, but not in direct sun, at room temperature of 20-24 °C (68-75 °F) with daily ventilation.

Under favorable conditions, first sprouts emerge in approximately 3 weeks; the main germination usually takes 1-2 months, and individual seeds may delay for up to three months. Seedlings develop slowly and are sensitive to surface desiccation. Pricking out is carried out after several true leaves have formed, into individual small pots with acidic substrate.

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Leptospermum requires a bright sunny location. In summer, it is beneficial to move the plant outdoors to a bright, warm spot sheltered from harsh winds.

In winter, a cool, bright dormancy period at a temperature of 4-10 °C (39-50 °F) is essential - this specifically ensures profuse flowering in the following season. In warm winter conditions, the plant stretches, drops foliage, and rarely blooms.

During the growth period, watering is generous, strictly with soft water - Leptospermum does not tolerate lime. Complete drying of the root ball is fatal to it, but standing water is equally unacceptable. The plant responds well to misting with soft water in hot weather.

The substrate must be acidic, loose, and breathable, without lime: ready-made potting soil for rhododendrons and azaleas is suitable, or a mix of acidic peat, leaf mould, and coarse sand with added perlite. Drainage is placed at the bottom of the pot. Repotting is carried out in spring as roots fill the container, carefully preserving the root ball.

Feeding is carried out once every two weeks during active growth using fertilizer for rhododendrons or another formula for acid-loving plants. During the dormant period, fertilizers are not applied.

The plant tolerates pruning well and is easily shaped into a compact bushy form, which is why it is eagerly cultivated as a bonsai. In addition to seeds, Leptospermum is propagated by semi-hardwood cuttings in spring.