Hydrangea Soil & Care Guide
Hydrangea, a perennial plant, comes in a wide range of varieties like:
Bigleaf hydrangea, French hydrangea, or Mophead hydrangea (Hydrangea macrophylla)
Oakleaf hydrangea (Hydrangea quercifolia)
Peegee hydrangea (Hydrangea paniculata)
Annabelle or smooth hydrangea (Hydrangea arborescens)
- Mountain hydrangea (Hydrangea serrata)
- Climbing hydrangea (Hydrangea petiolaris)
Fun fact: Bigleaf and smooth hydrangea usually have sterile flowers. But lacecap hydrangeas, a cultivar of H. macrophylla, can have fertile and sterile flowers. And unlike fertile flowers, sterile flowers won’t attract bees!
You also have patented types of hydrangea, including Endless Summer hydrangea (Hydrangea macrophylla) and Limelight hydrangea (Hydrangea paniculata).
But what soil should you use for these hydrangea varieties?
Let’s explore the best soil and other essentials about planting hydrangeas:
1. The Perfect Hydrangea Soil
For growing hydrangeas, you need moist, well draining soil.
Here’s what makes the best soil for your hydrangea plant:
Hydrangeas prefer soil with organic matter (like Rosy), which improves water retention and adds nutrients (like nitrogen and potassium) crucial for the new growth of flower buds.
Potted hydrangea can thrive in acidic soil and alkaline soil. Interestingly, in some varieties like Hydrangea macrophylla and Hydrangea serrata, the hydrangea color may change with the soil pH!
Hydrangea potting soil should be porous for easy drainage and good aeration.
That’s why Rosy’s Hydrangea Soil is better than sandy soil or heavy clay soil, which may cause dry roots and root rot.
2. Best Practices for Hydrangea Care
Here are essential tips for growing hydrangeas:
Plant hydrangeas either in autumn or early spring.
Before planting hydrangeas, ensure the pot is 2-3 times wider than the root ball.
Keep your hydrangea plants in partial shade or a mix of morning sun and afternoon shade. Most hydrangeas, except H. paniculata, won’t thrive in full sun.
Water hydrangea whenever the top inches of soil start to dry since the plant prefers moist soil.
Fertilize your hydrangea plant with feed or mulch during the growing season.
- Ideally, prune hydrangea in winter to remove old wood and encourage an early summer bloom of flower clusters.
3. Proven Tips to Change Hydrangea Color (Flower Color)
Species like Bigleaf hydrangea (French hydrangea) change flower color based on the soil pH.
So here’s how to get a specific hydrangea flower color:
Blue hydrangea: soil pH below 5.5 (acidic soil) and availability of aluminum.
Purple bloom: pH level between 5.5 to 6.5 (acidic to neutral).
Pink blooms: soil pH above 6.5 (alkaline soil).
Generally, patented flower varieties of hydrangea, like Endless Summer, have their own bloom color kits. But you can also add aluminum sulfate or garden lime to modify soil pH.
Moreover, it’s easier to change blue flowers to pink blooms than to change pink flowers to blue blooms since alkaline soil makes aluminum unavailable for plants.
Note: Hydrangea flower or bloom color change can take months. And a hydrangea bloom with green or white flowers won’t change its flower color, regardless of the soil pH.