BONSAI BOTANY SHEET

ZELKOVA NIRE

Common Name: ZELKOVA - Family: ULMACEAE

Zelkova bonsai is one of the most popular varieties for its upside-down broom formation due to its fine, natural branching. It is an elegant, rustic plant, perfect for those looking for a bonsai with harmonious forms and very decorative reduced foliage.

🌍 Origin and characteristics

• A member of the Ulmaceae family, it is native to Japan, Korea and China.
• In the wild, it is a deciduous tree with a straight trunk and gray bark, widely used in urban boulevards in Asia.
• The leaves are small, serrated and pointed, bright green, turning yellow or orange in autumn.
• Widely used in bonsai for its neat habit and great capacity for fine branching.

☀️ Ideal exposure

• Prefers full sun to stimulate compact branching and small leaves.
• In hot summer, it can benefit from half-shade in the middle hours.
• In winter it should be protected from frost below -3°C, especially in small pots.

💧 Watering

• Keep the substrate slightly moist, avoiding both stagnation and complete dryness.
• In summer or warm climates, watering 1-2 times daily may be necessary.
• In winter, decrease the frequency but do not let the substrate dry out completely.
• Prefer non-calcareous or slightly acidified water.

🌱 Fertilization

• Spring and early summer (March-July): complete organic or lightly nitrogenous fertilizer.
• Fall (September-October): fertilizer with more phosphorus and potassium to strengthen tissue before resting.
• Discontinue in hot summer and winter months (if it is dormant).
• Fertilize every 15-30 days or use slow-release fertilizer pellets.

✂️ Pruning and stapling

• Structure pruning is done in late winter, before vegetative awakening.
• Continuous pruning during the growing season: shorten new shoots to 2-3 leaves.
• Thinning inner branches periodically to encourage light and aeration.
• If grown for fall effect, avoid pruning in late summer to avoid losing coloration.

🧵 Zelkova bonsai tree tying

• Young branches are shaped well with aluminum wire in spring or fall.
• Extreme shaping is not needed; Zelkova forms well with pruning and stapling.
• Use tension rods for gentle bending on main branches.
• Check every 3-4 weeks to avoid wire marks on smooth bark.

🔄 Repotting

• Every 2-3 years, in spring (March-April), just before vegetative awakening.
• Recommended substrate:
  • Temperate climates: 70% Akadama + 30% Pumice.
  • Hot or dry climates: add 10-15% organic potting soil or zeolite to retain more moisture.
• Does not tolerate too drastic root pruning. Better gradual interventions.

🐛 Common diseases and pests

Diseases

• Root rot: due to too compact or wet substrate.
• Powdery mild ew or white mold: under humid conditions and poor ventilation.

Pests

• Aphids on young spring shoots.
• Red spider m ite and mealybugs in hot, dry periods.

📦 Recommended products

• Organic fertilizer for small leaf bonsai trees
• Substrate Akadama, pumice and organic part
• Aluminum wire for binding bonsai trees
• Pointed scissors for stapling and thinning
• White oil or natural aphid/cochineal insecticide

📝 Conclusion

Zelkova bonsai is an excellent choice for those looking for an elegant, branching tree, suitable even for beginners. It grows neatly, responds well to pruning and stapling, and takes on beautiful fall color if grown properly.

🔎 Trivia: Zelkova, Nire and Chinese Elm - the differences
There is often confusion between Zelkova serrata (Japanese zelkova), Zelkova nire (smaller, wrinkled leaf variety) and Chinese Elm(Ulmus parvifolia).
Although similar in appearance and bonsai style:

• Chinese Elm: semi-evergreen, more hardy, with flaky bark.
• Zelkova serrata: deciduous, regular leaf, more elegant and classical.
• Zelkova nire: ornamental variety with very small, wrinkled leaf, perfect for mame and shohin.

All excellent bonsai, but with slightly different requirements and unique habit.