JACKS CLASSIC - Hydrangea Blue - 7-3-3
Best soil treatment for gardeners wanting vibrant blue hydrangea blooms.
Achieve vibrant blue blooms on your hydrangeas with Jack's Classic® Hydrangea BLUE fertilizer. This specialized formula features a 7-3-3 NPK ratio, providing essential nutrients for lush, deep green foliage and the desired blue flower color. It uniquely incorporates acidifying ingredients, including aluminum sulfate, to help maintain the necessary soil pH for blue coloration. This 1.5lb package is designed specifically for hydrangea enthusiasts seeking reliable results and is a water-soluble powder for easy application.
$16.99
Owner Satisfaction
4.6
/ 5
Category Rank
1939
/ 4425
#1939 in Fertilizers
Price vs Category Average
-72%
Below average
Nitrogen Percentage
7.0
/ %
Who it's for
- Gardeners seeking vibrant blue hydrangea blooms
- Impatient growers wanting fast-acting nutrient delivery
- Horticulturists prioritizing flower production over excessive foliage
Who should skip it
- Gardeners with alkaline soil or no pH testing tools
- Owners of diverse gardens needing an all-purpose fertilizer
- Beginners uncomfortable with precise chemical measurements
Performance breakdown
Color Enhancement Efficacy
High aluminum sulfate content reliably shifts soil pH for deeper blues.
Application Convenience
Water-soluble powder formula ensures rapid mixing and effortless root zone delivery.
Nutrient Balance
The 7-3-3 ratio provides steady growth without excessive, leggy foliage production.
Formula Specialization
Tailored specifically for acid-loving plants to ensure consistent, predictable results.
Market Accessibility
Strict shipping restrictions limit availability for many West Coast gardeners.
Packaging Efficiency
Compact 1.5lb container is ideal for small gardens but lacks bulk value.
Key Specs
Nitrogen Percentage
7.0%
Phosphorus Percentage
3.0%
Potassium Percentage
3.0%
Fertilizer Form
Water Soluble Powder
Fertilizer Source
Synthetic
Container Weight
1.5 lbs
Target Plant Type
Flowers, Trees and Shrubs, Acid-Loving Plants
Active Ingredient
50% aluminum sulfate
Features
- Promotes vibrant blue hydrangea blooms
- Supports lush, deep green foliage
- Contains essential micronutrients
- Acidifies soil for blue color
- Water-soluble powder for easy use
- Specifically for hydrangeas
What customers say
Gardeners consistently praise the exceptional effectiveness of Jacks Classic Hydrangea Blue, noting reliable and vibrant color transformation. The specialized 7 3 3 formula delivers noticeable improvements in bloom intensity and overall plant vigor, making it a trusted solution for achieving deep blue hues. Users find the water soluble application straightforward and efficient. This product is highly valued for its quality results, establishing it as a staple for serious hydrangea enthusiasts seeking predictable performance.
Know before you buy
This formula contains aluminum sulfate, which lowers the soil pH. Hydrangeas require acidic soil to absorb the aluminum necessary to produce blue pigments in their petals.
It is specifically designed for bigleaf hydrangeas (Hydrangea macrophylla) and mountain hydrangeas, which are the varieties capable of changing color based on soil pH. It will not change the color of white-flowering varieties.
For best results, apply the water-soluble mixture throughout the growing season. Always follow the specific dilution instructions on the label to avoid over-fertilizing your plants.
While it is formulated for hydrangeas, the acidifying properties can benefit other acid-loving plants. However, monitor your soil pH levels to ensure you are not making the environment too acidic for those specific species.
This is a synthetic, water-soluble fertilizer. It is designed for quick nutrient uptake and precise control over soil acidity, which is essential for achieving consistent blue blooms.
Still have a question?
Ask Hayley anything about this product before you decide.
Ready to buy?
$17