Nikko Blue Hydrangea: Care and secrets to stunning blue bloom

Nikko Blue Hydrangea (Hydrangea macrophylla 'Nikko Blue') is a popular hydrangea variety known for its large, mophead blooms and its ability to produce stunning blue flowers. Achieving and maintaining the blue coloration of the blooms depends on the pH of the soil. Here are some care tips and secrets to help you enjoy a beautiful display of blue blooms:

Soil pH:

Nikko Blue Hydrangeas produce blue flowers in acidic to neutral soils (pH 5.2-6.2). The presence of aluminum in the soil is crucial for the blue coloration. In acidic soils, aluminum is more available for uptake by the plant.

Soil Amendments:

To lower the soil pH and enhance aluminum availability, amend the soil with aluminum sulfate or elemental sulfur. Follow package instructions for application rates.

Testing Soil pH:

Regularly test the soil pH to ensure it remains in the acidic to neutral range. Soil test kits are available at garden centers, or you can send a soil sample to a local agricultural extension service for more accurate results.

Watering:

Keep the soil consistently moist but not waterlogged. Hydrangeas prefer well-draining soil. Mulching around the base of the plant can help retain moisture and regulate soil temperature.

Fertilizing:

Use a fertilizer specifically formulated for hydrangeas or acid-loving plants. Look for a fertilizer with a higher level of phosphorus, as this can also encourage flower production. Apply fertilizer in spring and early summer.

Pruning:

Prune Nikko Blue Hydrangeas in late winter or early spring before new growth emerges. Remove dead or weak wood and trim back old stems to encourage new growth and more blooms. Be cautious not to remove potential flower buds.

Sunlight:

While Nikko Blue Hydrangeas tolerate some shade, they generally produce more vibrant blooms when exposed to morning sunlight. Provide them with at least 4-6 hours of sunlight per day.

Winter Protection:

In colder climates, consider providing winter protection by covering the plant with burlap or applying a thick layer of mulch around the base to insulate the roots.

Avoid Lime:

Lime increases soil alkalinity, which can shift the flower color towards pink. If you desire blue blooms, avoid applying lime around your Nikko Blue Hydrangea.

Consistent Care:

Consistency is key. Once you've achieved the desired blue color, maintaining the proper soil conditions is crucial for continued success.

By paying attention to soil pH, providing the right nutrients, and maintaining proper care, you can enjoy the stunning blue blooms of Nikko Blue Hydrangeas in your garden. Keep in mind that factors like natural variations in soil composition and local water quality can influence the success of color manipulation.