1. Understanding Hydrangea Blooming Cycles
Hydrangeas produce flowers on either old wood (previous year's growth) or new wood (current season's growth), depending on the species. For example, Hydrangea macrophylla (bigleaf hydrangea) blooms on old wood, while Hydrangea paniculata (panicle hydrangea) blooms on new wood. Deadheading—removing spent flowers—can encourage more blooms, but timing and technique depend on the plant's growth habit.
2. Why Deadheading Promotes More Flowers
From the plant's perspective, deadheading redirects energy from seed production (which occurs after flowering) to vegetative growth and new flower bud formation. By removing faded blooms, you signal the plant to focus on producing new shoots and buds rather than investing resources in seeds. This is especially beneficial for reblooming varieties like Hydrangea macrophylla 'Endless Summer,' which can flower on both old and new wood.
3. How to Deadhead Hydrangeas Correctly
For hydrangeas that bloom on old wood (e.g., bigleaf, oakleaf, mountain hydrangeas):
- Deadhead immediately after the flowers fade in late summer or early fall. This allows time for new buds to form on old wood before winter.
- Cut just above the first set of healthy leaves or buds below the spent flower, using clean, sharp pruners.
For hydrangeas that bloom on new wood (e.g., panicle, smooth hydrangeas):
- Deadhead in late winter or early spring before new growth emerges.
- Trim back to a pair of strong buds or nodes to encourage branching and more flower spikes.
4. Avoiding Common Deadheading Mistakes
- Over-pruning: Cutting too far down on old-wood bloomers can remove next year's flower buds, reducing blooms.
- Late deadheading: Delaying removal of spent flowers on old-wood varieties may leave insufficient time for bud formation.
- Damaging buds: Rough cuts or tearing stems can stress the plant and invite disease.
5. Additional Care Tips for Maximum Blooms
To complement deadheading, ensure your hydrangeas receive:
- Adequate water: Consistent moisture supports bud development, especially during dry spells.
- Proper fertilization: Use a balanced fertilizer in early spring to nourish new growth.
- Appropriate sunlight: Most hydrangeas prefer morning sun and afternoon shade to avoid stress.
