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Hydrangea Fertilizer: Everything You Need to Know for Healthy Growth

Proper fertilization is essential for maintaining the health and vibrancy of your hydrangea bush or tree, ensuring robust growth and abundant flowers throughout the growing season.

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Hydrangeas are cherished for their beautiful blooms and versatility in the garden. Proper fertilization is key to keeping these stunning plants healthy and vibrant. This comprehensive guide covers everything you need to know about hydrangea fertilizer, including types, application methods, timing, nutrient requirements, and common issues.

Understanding Hydrangeas

Before diving into fertilization, it’s important to understand the different types of hydrangeas and their unique needs:

Hydrangea macrophylla (Bigleaf Hydrangea): This species is known for its large, showy flower clusters, which bloom in shades of blue or pink, depending on soil pH. It thrives in moist, well-drained soils and prefers partial shade.

  • Native: Native to Japan, China, Korea, and Southeast Asia.
  • Bloom Time: Typically blooms from late spring to early fall.
  • Size: Grows 2 to 6 feet (60-180 cm) tall and wide.

Hydrangea paniculata (Panicle Hydrangea): This type is recognized for its conical flower clusters. It blooms on new wood, making it more resilient to pruning. It can adapt to a range of soil types and pH levels.

  • Native: Native to Asia, including Japan and China.
  • Bloom Time: Blooms from mid-summer to fall.
  • Size: Can reach heights of 8 to 20 feet (2.4 to 6 meters), with a spread of 6 to 8 feet (1.8 to 2.4 meters).

Hydrangea quercifolia (Oakleaf Hydrangea): This variety is hardy and adaptable, producing beautiful white blooms that age to pink. It is notable for its unique oak-shaped leaves.

  • Native: Native to the southeastern United States.
  • Bloom Time: Blooms from late spring to mid-summer.
  • Size: Grows 2 to 8 feet (60-240 cm) tall and wide.

Hydrangea arborescens (Smooth Hydrangea): This species produces large flower heads and is often used for hedging. It blooms on new growth and prefers well-drained soil.

  • Native: Native to the eastern United States.
  • Bloom Time: Blooms from early summer to fall.
  • Size: Grows 3 to 6 feet (90-180 cm) tall and wide

Hydrangea serrata (Mountain Hydrangea): Known for its serrated leaf margins and compact growth habit, this species produces beautiful lacecap or mophead flowers. It thrives in well-drained, slightly acidic soils and is adaptable to various light conditions.

  • Native: Native to Japan and Korea.
  • Bloom Time: Blooms from early to late summer.
  • Size: Typically grows 2 to 4 feet (60-120 cm) tall and wide.

Limelight Hydrangea, Panicle Hydrangea, Hydrangra Paniculata, Hydrangea, Hydrangea flowers, White HydrangeaLimelight Hydrangea – Hydrangea paniculata or Panicle Hydrangea

The Importance of Fertilizing Your Hydrangea Bush or Tree

Fertilization plays a crucial role in the health and growth of hydrangeas:

  • Promotes Growth: Nutrients are vital for leaf and stem development, ensuring the plant has the vigor to support its growth.
  • Encourages Blooms: Adequate fertilization helps produce vibrant and abundant blooms, enhancing the overall aesthetic of the garden.
  • Improves Resilience: Well-fed hydrangeas are more resilient to diseases and pests, helping maintain their health throughout the growing season.

Types of Fertilizers for Hydrangeas

Selecting the right fertilizer for hydrangeas can significantly impact their growth and blooming. Here’s a breakdown of the various types of fertilizers and how to choose the best one for your hydrangeas:

Granular Fertilizers

Granular fertilizers are slow-release options that gradually provide essential nutrients to hydrangeas over time. They are convenient to apply and minimize the risk of over-fertilization. When choosing granular fertilizers:

  • Look for a balanced NPK ratio: Aim for fertilizers with ratios like 10-10-10 or 12-4-8, which supply equal parts nitrogen (N), phosphorus (P), and potassium (K).
  • Choose formulations designed for flowering plants: Select products specifically labeled for hydrangeas or flowering shrubs to meet their nutrient requirements effectively.

Liquid Fertilizers

Liquid fertilizers offer quick nutrient uptake and are particularly useful during the growing season when hydrangeas require more immediate nourishment. These can be applied as needed throughout the growing season. To choose the right liquid fertilizer:

  • Opt for a balanced or bloom-boosting formulation: Use liquid fertilizers with an NPK ratio suitable for flowering plants. These fertilizers often contain higher phosphorus levels to promote blooming.
  • Consider the frequency of application: Liquid fertilizers can be applied every few weeks during the growing season, but follow the manufacturer’s instructions to avoid over-fertilization.

Organic Fertilizers

Organic fertilizers are derived from natural sources and are excellent for environmentally conscious gardeners. Common organic options include:

  • Compost: Incorporate well-aged compost into the soil at planting or as a top-dressing. It provides a slow release of nutrients while improving soil structure.
  • Well-rotted Manure: A great source of nitrogen and other nutrients, manure should be well-composted to avoid burning plants.
  • Bone Meal: This organic option is high in phosphorus, making it a great choice for encouraging root development and vibrant blooms. Use it at planting or as a supplement during the growing season.
  • Fish Emulsion: This liquid organic fertilizer is rich in nitrogen and can be used to promote lush foliage. However, ensure they are diluted appropriately and follow the application guidelines.

Specialty Hydrangea Fertilizers

Some brands offer fertilizers specifically formulated for hydrangeas. These products often contain the right balance of nutrients tailored to their needs, including micronutrients like magnesium and iron.

Pinky Winky Hydrangea, Hydrangea Paniculata Pinky Winky, Hydrangea Pinky Winky, Panicle Hydrangea Pinky Winky, Paniculate Hydrangea Pinky Winky, Pink Flowers, Pinky Winky Hydrangea – Hydrangea paniculata or Panicle Hydrangea

Organic vs Inorganic Hydrangea Fertilizers: Pros and Cons 

These fertilizers differ primarily in their composition and impact on soil health.

Organic fertilizers are derived from natural sources, such as compost, manure, or bone meal, and improve soil structure and microbial activity while providing slow-release nutrients. They promote long-term soil health and are environmentally friendly.

Pros:

  • Enhance soil structure and microbial activity, promoting long-term soil health.
  • Provide a slow release of nutrients, reducing the risk of over-fertilization.
  • Environmentally friendly and safe for the ecosystem.

Cons:

  • Typically more expensive and may require larger quantities for effectiveness.
  • Nutrient content may be less concentrated, leading to slower results.

In contrast, inorganic fertilizers are synthetically produced and offer quick-release nutrients that lead to rapid plant growth. While they can deliver immediate results, they may not enhance soil quality over time and can risk nutrient runoff.

Pros:

  • Fast-acting and can quickly supply nutrients for immediate plant needs.
  • Often more affordable and readily available.

Cons:

  • Can lead to nutrient runoff and environmental issues if over-applied.
  • May harm soil health over time and create dependency on synthetic inputs.

Hydrangea macrophylla, Bigleaf Hydrangea, Big Leaf Hydrangea, Blue HydrangeaAll Summer Beauty – Hydrangea macrophylla or Bigleaf Hydrangea

How and When to Fertilize Hydrangeas

Before applying fertilizer, conduct a soil test to determine pH and nutrient levels. This will help you select the right type and amount of fertilizer.

Granular Fertilizer:

  • When to Apply: Early spring, as new growth begins.
  • How to Apply: Spread evenly around the base of the plant, avoiding direct contact with the stems.
  • Post-Application: Water thoroughly to help the nutrients penetrate the soil.

Liquid Fertilizer:

  • When to Apply: Early spring and again in mid-summer if needed.
  • How to Apply: Dilute according to the manufacturer’s instructions and apply to the soil around the base of the plant.
  • Best Timing: Apply early morning or late afternoon to minimize evaporation.

Organic Options:

  • When to Incorporate: Early spring.
  • How to Apply: Mix compost into the soil to enrich the planting area. Organic fertilizers can be used as a top-dressing around the plants during the growing season.

Timing Tips

Spring Application: Fertilizing in early spring supports new growth and blooming.

Mid-Season Boost: A second application in mid-summer can help sustain blooms, particularly for varieties that bloom on new wood, such as panicle, smooth, and mountain hydrangeas.

Avoid Late Fertilization: Refrain from fertilizing late in the growing season, as this can encourage new growth that may not harden off before winter.

Consider Fertilizer Type:

  • Slow-Release Fertilizer: Apply once or twice a year. Lightly cover it with soil to activate it.
  • Timed-Release Fertilizer: Follow packaging guidelines, typically apply every few months.
  • Fast-Release Fertilizer: Apply lightly in March, May, and July. Spread it around the plant’s drip line and water well afterward.

Annabelle Hydrangea, White Hydrangea, Hydrangea arborescens, Smooth HydrangeaAnnabelle Hydrangea – Hydrangea arborescens or Smooth Hydrangea

Adjusting Soil pH to Change Hydrangea Flowers Color

The color of hydrangea flowers, particularly in certain species, can be influenced by the pH of the soil. Understanding how to adjust soil pH is essential for achieving the desired bloom color—blue, pink, or purple. Here’s how to manage soil pH effectively for various hydrangea types:

Which Hydrangeas Are Affected?

Hydrangea macrophylla (Bigleaf Hydrangea): This species is the most sensitive to soil pH changes, particularly varieties such as Nikko Blue (Produces blue flowers in acidic soils and pink in alkaline conditions) or Endless Summer

Hydrangea serrulata (Japanese Hydrangea): Similar to Hydrangea macrophylla, these hydrangeas can also show variations in flower color based on soil pH.

How Soil pH Affects Color

  • Blue Flowers: In acidic soils (pH 5.0–5.5), Hydrangea macrophylla absorbs aluminum ions, resulting in blue flowers.
  • Pink Flowers: In alkaline soils (pH 6.0–6.5), Hydrangea macrophylla cannot take up aluminum, leading to pink blooms.
  • Purple Flowers: Some hydrangeas can produce purple flowers in soils with a pH level between acidic and alkaline.

Testing Soil pH

Before making adjustments, it’s crucial to test your soil’s pH. You can use:

  • Soil Test Kits: Available at garden centers or online, these kits provide accurate readings of soil pH and nutrient levels.
  • Local Extension Services: Many agricultural extension offices offer soil testing services at a nominal fee.

Adjusting Soil pH

Once you determine your soil’s pH, you can make adjustments to achieve your desired flower color:

For Blue Flowers (Acidic Soil)

  • Add Aluminum Sulfate: Follow the package instructions to apply this amendment, which lowers pH and supplies aluminum, promoting blue coloration.
  • Elemental Sulfur: This gradually decreases soil pH, but results may take several months to manifest, so plan your application in advance.
  • Mulching: Acidic materials like pine needles or shredded oak leaves can be used as mulch to help sustain lower pH levels.

For Pink Flowers (Alkaline Soil)

  • Add Lime: To raise the soil pH and encourage pink blooms, mix agricultural lime or dolomitic lime into the soil. Be sure to follow the package instructions for application rates based on your soil test results.

Peegee Hydrangea, Hydrangea paniculata Grandiflora, Panicle Hydrangea, Hydrangea treePeegee Hydrangea – Hydrangea paniculata ‘Grandiflora’

Troubleshooting Common Issues

Poor Growth: If your hydrangeas are not thriving, it may be due to insufficient nutrients, poor soil drainage, or incorrect pH levels. Conduct a soil test to identify the issue.

Yellowing Leaves: Chlorosis may indicate nitrogen deficiency or iron deficiency (especially in alkaline soils). Adjust your fertilization regimen accordingly.

Reduced Blooms: If your hydrangeas are not flowering well, they may need more phosphorus or potassium. Consider using a fertilizer with a higher middle number in the NPK ratio.

Over-fertilization: Excessive fertilizer can lead to leaf burn and diminished blooming. Always follow the recommended application rates.

Hydrangea Fertilization Myths

All Hydrangeas Require the Same Fertilizer: Different species and varieties have unique nutrient requirements. Understanding your specific hydrangea type is crucial for proper care.

More Fertilizer Equals More Blooms: Over-fertilization can harm plants. It’s essential to provide balanced nutrients at the right times.

Fertilizing in Winter is Beneficial: Fertilizing during the dormant season can lead to nutrient leaching and may harm the plant. Stick to spring and mid-summer applications.

Strawberry Vanilla Hydrangea, Vanilla Strawberry Hydrangea, Vanille Fraise Hydrangea, Renhy HydrangeaStrawberry Vanilla Hydrangea – Hydrangea paniculata or Panicle Hydrangea

Frequently Asked Questions

What is the best fertilizer for hydrangeas?

The best fertilizer for hydrangeas is a balanced, slow-release fertilizer with an NPK ratio of 10-10-10 or similar. Specialty fertilizers formulated for flowering shrubs or specifically for hydrangeas often include micronutrients that promote healthy growth and blooming. Organic options like compost or well-rotted manure can also be beneficial.

What month do you fertilize hydrangeas?

Fertilization for hydrangeas is typically done in early spring as new growth begins. A second application can be made in mid-summer to provide a boost during the growing season, particularly for varieties that bloom on new wood.

Do coffee grounds help hydrangeas bloom?

Yes, coffee grounds can help hydrangeas bloom by adding organic matter and slightly acidifying the soil. However, they should be used in moderation and not relied upon solely for fertilization. It’s best to mix them into the compost or soil to improve overall soil health.

What makes hydrangeas bloom better?

To encourage better blooming in hydrangeas, ensure they receive adequate sunlight (at least 4-6 hours a day), maintain consistent moisture without overwatering, and use the appropriate fertilizer based on soil pH. Additionally, regular pruning, especially for varieties that bloom on new wood, can promote more vigorous growth and flowering.

How do I get my hydrangeas to bloom more?

To enhance blooming in hydrangeas, follow these tips:

  • Proper Fertilization: Use a balanced fertilizer in spring and consider a mid-summer boost.
  • Adequate Watering: Ensure consistent moisture, especially during dry spells.
  • Pruning: Prune appropriately based on the type of hydrangea you have; for those that bloom on new wood, pruning in late winter or early spring can stimulate more blooms.
  • Mulching: Apply mulch to retain moisture and suppress weeds, creating a healthier growing environment.

Guide Information

Hardiness 3 - 9
Heat Zones 1 - 9
Plant Type Shrubs
Plant Family Hydrangeaceae
Genus Hydrangea
Exposure Full Sun, Partial Sun
Season of Interest Spring (Late), Summer (Early, Mid, Late), Fall
Maintenance Low
Water Needs Average
Soil Type Clay, Loam, Sand
Soil pH Acid, Alkaline, Neutral
Soil Drainage Moist but Well-Drained
Characteristics Dried Arrangements, Cut Flowers, Showy
Attracts Butterflies, Hummingbirds
Landscaping Ideas Patio And Containers, Hedges And Screens, Beds And Borders

Garden Examples

A Lovely Contemporary Garden Idea
A Majestic Walkway
An Elegant Shady Corner
Compare All Hydrangea
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Guides with
Hydrangea
While every effort has been made to describe these plants accurately, please keep in mind that height, bloom time, and color may differ in various climates. The description of these plants has been written based on numerous outside resources.

Guide Information

Hardiness 3 - 9
Heat Zones 1 - 9
Plant Type Shrubs
Plant Family Hydrangeaceae
Genus Hydrangea
Exposure Full Sun, Partial Sun
Season of Interest Spring (Late), Summer (Early, Mid, Late), Fall
Maintenance Low
Water Needs Average
Soil Type Clay, Loam, Sand
Soil pH Acid, Alkaline, Neutral
Soil Drainage Moist but Well-Drained
Characteristics Dried Arrangements, Cut Flowers, Showy
Attracts Butterflies, Hummingbirds
Landscaping Ideas Patio And Containers, Hedges And Screens, Beds And Borders
Compare All Hydrangea
Compare Now
Explore Great Plant Combination Ideas
Hydrangea
Guides with
Hydrangea

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