Hydrangeas are a stunning addition to Southwestern Ontario gardens, thriving in Zones 5–6 when given the right care. These versatile shrubs produce abundant blooms and adapt well to local growing conditions.
Light and Water: Plant in a location with morning sun and afternoon shade to prevent leaf scorch. Water deeply and consistently at the base of the plant, especially during hot, dry summers, to maintain soil moisture and reduce fungal disease risk.
Soil and Mulch: Hydrangeas prefer well-draining, nutrient-rich soil. Amend with compost to improve structure and fertility, then apply 5–8 cm of organic mulch (shredded bark or compost) around the base to retain moisture and keep roots cool.
Feeding: Apply a slow-release, balanced fertilizer (such as Holly-tone) in mid-to-late spring to support blooming. Stop fertilizing after July to avoid encouraging tender new growth before winter.
Pruning by Type: Always prune according to type to avoid removing next year's flower buds. Panicle and Smooth hydrangeas bloom on new wood and should be pruned in late winter or early spring (March/early April).
Bigleaf and Oakleaf varieties bloom on old wood and require pruning immediately after flowering (by August 1st).
Winter Care: Provide a final deep watering in late fall. For sensitive varieties, wrap in burlap or apply heavy mulch (15–30 cm) to protect buds from winter damage.
