Celtis

Fertilizing

For optimal growth, fertilize Celtis bonsai every two to three weeks during the growing season from early spring through autumn. The Celtis Africana variety grows more slowly and requires less frequent feeding - monthly applications are sufficient. Use a balanced organic fertilizer to promote healthy development of the tree's characteristic fine twig structure and delicate green leaves.

Placement

Position your Celtis bonsai in full sun for best results. While it can technically be grown indoors, this species thrives when placed outside in a sunny spot. Exercise caution on particularly hot days, as the tree can dry out quickly. Ensure proper air circulation and monitor moisture levels closely, especially during peak summer heat. The Celtis sinensis develops attractive orange fruits in early summer following spring flowering, making proper placement crucial for fruit development.

Pruning

Regular pruning is essential for developing the Celtis bonsai's signature fine ramification. When the tree is in development, allow branches to grow freely until they reach desired thickness before cutting back. During refinement, prune branches back to 2-3 buds on new wood to promote dense branching. Avoid pruning into old wood as this can weaken the tree. For optimal results, time major pruning work for late spring when the leaves become slightly leathery, as this promotes better healing and reduces sap loss.

Winter pruning should focus on basic maintenance - removing dead wood and slightly adjusting the silhouette. The timing of structural pruning is critical since the tree heals poorly during dormancy. Let the tree's natural growth habit guide your pruning decisions, as branches naturally transition from horizontal at the bottom to more vertical in the apex.

Repotting

Repot young, developing Celtis bonsai every 2-3 years in early spring using a well-draining mix of akadama, pumice, and crushed lava with some agricultural carbon. Mature specimens can go longer between repotting but monitor for signs of declining drainage. The roots fill containers quickly, forming dense mats of fine roots near the surface. If water penetration becomes poor but full repotting isn't needed, remove the top layer of soil and roots, then top dress with fresh medium and sphagnum moss.

Watering

The Celtis requires frequent watering but is sensitive to overly wet conditions. Water thoroughly when the top layer of soil begins to dry, taking care not to let the root mass dry out completely. Use proper well-draining soil and containers to prevent root rot. During hot periods, the tree may need multiple waterings per day. If the tree has been recently repotted, maintain slightly higher humidity through misting to help with recovery.

References

Bonsai Empire - Celtis Care Guide Bonsai Tree - Seasonal Work on Hackberry