Trident maple

Fertilizing

For younger Trident Maple bonsai trees, use a fertilizer high in nitrogen during the growing season to promote strong growth and trunk thickening. Apply weekly during the first month of spring growth, then twice monthly thereafter. When fall arrives, switch to a lower nitrogen, higher phosphorus fertilizer to help prepare the tree for winter. Older trees in refinement stage require less nitrogen to control growth and maintain smaller leaves. Some experts recommend pausing fertilization in spring if the tree is in refinement stage to prevent overly large leaves.

In summer, continue regular fertilizing if developing the trunk, but avoid fertilizing refined trees to prevent large leaf development. Fall is a critical fertilizing period as growth slows - use organic fertilizer then to provide essential nutrients before dormancy.

Placement

Your Trident Maple bonsai should be grown outdoors in a bright location with morning sun and afternoon shade during hot summer months. While they can tolerate more sun than Japanese Maples, some protection from intense afternoon sun is beneficial. The trees need a dormant period in winter but must be protected when temperatures drop below -5°C (23°F). An unheated greenhouse, cold frame, or garage makes an ideal winter shelter.

The roots have higher than normal moisture content and are prone to frost damage, so proper winter protection is critical. For those in cooler climates, the trees can be grown outdoors in summer but should be moved to winter protection before temperatures reach freezing. Ensure good air circulation while avoiding strong winds that can damage foliage.

Pruning

Spring is the optimal time for major pruning, just before or during bud break. You can cut back up to 65% of the roots during repotting, focusing on removing larger roots while preserving the finer feeder roots. During the growing season, continuously pinch back new shoots to develop ramification and maintain the desired silhouette. For mature trees, pinch young shoots very early to prevent thickening of outer twigs.

The tree responds well to defoliation techniques which can be performed in May if the tree is healthy and shoots have hardened off. Full defoliation works well for young trees, while partial defoliation leaving inner foliage is better for refined specimens. Summer provides opportunities for trunk chops or heavy cutbacks, though the tree should be vigorous and healthy before attempting major work. Winter allows for silhouette refinement on well-developed trees.

Repotting

Early spring before bud break is ideal for repotting Trident Maples, with some experts even repotting as early as January/February. New trees should be given 1-2 years to establish before their first repotting. After that, repot every 2-3 years, or annually for younger vigorous specimens. The soil mix should be well-draining - use a 2:1:1 mix of Akadama, Pumice, and Lava Rock for developing trees, transitioning to pure Akadama for refined specimens.

Unlike many species, Trident Maples tolerate bare-rooting well during repotting. The soil pH should be between 5-7. After repotting, keep the tree in a shaded, cool location for several weeks while it recovers. Older specimens require more careful handling during repotting but can still handle aggressive root pruning when needed.

Watering

During the growing season, especially summer, Trident Maples require frequent watering to maintain consistently moist but not waterlogged soil. Water thoroughly when the soil surface begins to dry. These trees are sensitive to water quality - if you notice black spots on leaf tips, consider using reverse osmosis or rainwater, particularly if your tap water TDS reading exceeds 300.

Reduce watering frequency in winter but maintain some moisture - a weekly watering is typically sufficient even if the soil appears damp. Avoid using water high in calcium content as this can lead to leaf yellowing. The trees are somewhat drought tolerant compared to other maple species but still need regular watering, particularly during hot weather. Always ensure proper drainage to prevent root rot issues.

References

Bonsai Express: Trident Maple Bonsai Guide Bonsai4Beginners: Trident Maple Care Guide Bonsai Grounds: Seasonal Maintenance Guide