Italian stone pine, Ref. 2902

Growing a bonsai from a Pinia (Pinus pinea), also known as the Italian stone pine, requires patience and careful maintenance. This species is known for its distinctive umbrella-shaped canopy, but with proper techniques, it can be shaped into a stunning bonsai.

1. Choosing the right material
You can start growing a Pinia bonsai through several methods from:
seeds (need 2-3 months cold stratification in a refrigerator before planting.
- cuttings (difficult, as pines do not root well from cuttings).
- young sapling (great option, as it allows you to start shaping early).
- yamadori (if you find a naturally stunted Pinia, it can be a great starting point).

2. Soil and Pot Selection
Soil: well-draining, slightly acidic, and low in organic matter. A good mix includes
akadama : pumice : lava rock (2:1:1), see here.
Pot: Initially, use a deep training pot to develop the roots. Once the tree is mature, put to a shallow bonsai pot.

3. Watering
Pinia bonsai prefers slightly dry conditions rather than constantly wet soil.
Water thoroughly but allow the top layer of soil to dry slightly between waterings.
Avoid overwatering, as it can lead to root rot.

4. Light and Temperature
Full Sun: Pinias thrive in bright, direct sunlight for at least 6-8 hours daily.
Temperature:
It tolerates hot summers well.
In winter, protect it from freezing temperatures. It prefers a dormant period at 5–10°C .

5. Pruning and Shaping
Structural Pruning: Done in late winter or early spring before new growth begins.
Candle Pinching: In late spring or early summer, shorten new shoots (candles) to encourage dense growth.
Wiring: best applied in autumn or early winter. Monitor the wire to prevent it from cutting into the bark.
Needle reduction: Older needles can be plucked in autumn to improve airflow and balance energy distribution.

6. Repotting
Frequency: every 3-5 years, depending on root growth.
Best Time: early spring before the tree starts active growth.
Root Pruning: be careful—never remove more than 30% of the roots to avoid stress.

7. Fertilization
Spring & Autumn: Use a balanced organic fertilizer to support steady growth.
Summer: Reduce feeding to avoid excessive elongation.
Winter: No fertilization is needed.

8. Pest and Disease Control
Common Pests: Aphids, spider mites, and scale insects.
Diseases: Fungal infections like root rot and needle blight. Ensure proper airflow and avoid overwatering.

9. Recommended Bonsai Styles
Formal Upright (Chokkan) – Straight trunk, classic look.
Informal Upright (Moyogi) – Slightly curved trunk for a natural appearance.
Slanting (Shakan) – The tree leans as if shaped by the wind.
Cascade (Kengai) – Mimics a tree growing down a mountainside.