Soil & potting mix
Best soil for Bigleaf Hydrangea 'Nikko Blue' (Hydrangea macrophylla 'Nikko Blue')
Also called Nikko Blue Mophead.
More about bigleaf hydrangea 'nikko blue'
About Bigleaf Hydrangea 'Nikko Blue'
Hydrangea macrophylla 'Nikko Blue' · also called Nikko Blue Mophead · flowering
'Nikko Blue' is a classic mophead bigleaf hydrangea with large rounded flower heads that turn vivid blue in acidic soil or pink in alkaline soil. A vigorous deciduous shrub blooming in summer on old wood, it needs moist, rich soil and shelter, and rewards correct pruning with its signature voluptuous blue domes.
Preferred mix: Rich, moist, well-drained soil
Watch for — Wrong flower colour: Blue needs acidic soil with free aluminium; in neutral or limy soil it turns pink or muddy. Acidify with sulphur/aluminium sulphate to hold blue.
Why bigleaf hydrangea 'nikko blue' needs this mix
Bigleaf Hydrangea 'Nikko Blue' is a Mediterranean dry-hillside plant — it wants a lean, sharply drained, slightly alkaline mix, and rots fast in rich, water-holding soil.
- Bigleaf Hydrangea 'Nikko Blue' evolved on stony, sun-baked slopes — its roots expect to dry out hard and quickly between rains, so the mix must drain almost as fast as you pour.
- A lean, low-nutrient mix keeps growth firm and aromatic; a rich one gives soft, sappy, flavourless growth that flops and rots.
- It tolerates and often prefers a slightly alkaline soil, the opposite of most houseplants.
For the full picture on what makes up a good mix, see our guide to the main types of soil and potting media — it explains why each ingredient above behaves the way it does.
What goes wrong with the wrong mix
The wrong soil is one of the most common reasons bigleaf hydrangea 'nikko blue' struggles, and the damage often shows up weeks later as a watering problem. For this species specifically:
- Rich, moisture-holding compost is the classic killer of bigleaf hydrangea 'nikko blue' — especially over a cold, wet winter, when the base of the plant simply rots.
- A peaty, acidic potting mix is doubly wrong: too wet and the wrong pH direction.
- No grit means the rootball stays damp for days, which a dry-climate root system never copes with.
Growing bigleaf hydrangea 'nikko blue' in ordinary rich, moisture-retentive compost. Lean it out with at least a third grit, and never let it sit wet over winter.
pH — does it matter for bigleaf hydrangea 'nikko blue'?
Bigleaf Hydrangea 'Nikko Blue' likes neutral to slightly alkaline soil, roughly pH 6.5-7.5. If your soil or compost is acidic, a little garden lime or extra grit nudges it the right way — the one common plant where you may add lime.
If you want to check or adjust it, the soil pH guide walks through testing and the safe ways to nudge a mix more acidic or more alkaline.
DIY mix vs a bagged one
Bagged "herb" or "Mediterranean" mixes are usually fine for bigleaf hydrangea 'nikko blue', but most standard composts need cutting hard with grit. The DIY ratio above is cheap and exactly right.
Drainage and the pot
Sharp drainage is everything: a terracotta pot with a big hole, gritty mix and never a saucer left full. Raised beds suit these herbs outdoors for the same reason.
A gritty mix barely breaks down, so bigleaf hydrangea 'nikko blue' needs little repotting — refresh the top layer and the grit every couple of years rather than potting on aggressively. When the time comes, our repotting guide for bigleaf hydrangea 'nikko blue' covers the timing and technique step by step.
Bigleaf Hydrangea 'Nikko Blue' soil — frequently asked questions
What is the best soil mix for bigleaf hydrangea 'nikko blue'?
2 parts standard peat-free compost or loam : 1 part coarse horticultural grit : 1 part perlite or coarse sand. Bigleaf Hydrangea 'Nikko Blue' evolved on stony, sun-baked slopes — its roots expect to dry out hard and quickly between rains, so the mix must drain almost as fast as you pour.
Can I use normal potting soil for bigleaf hydrangea 'nikko blue'?
Rich, moisture-holding compost is the classic killer of bigleaf hydrangea 'nikko blue' — especially over a cold, wet winter, when the base of the plant simply rots. Bagged "herb" or "Mediterranean" mixes are usually fine for bigleaf hydrangea 'nikko blue', but most standard composts need cutting hard with grit. The DIY ratio above is cheap and exactly right.
Does bigleaf hydrangea 'nikko blue' need a special pH?
Bigleaf Hydrangea 'Nikko Blue' likes neutral to slightly alkaline soil, roughly pH 6.5-7.5. If your soil or compost is acidic, a little garden lime or extra grit nudges it the right way — the one common plant where you may add lime.
Should I buy a bagged mix or make my own for bigleaf hydrangea 'nikko blue'?
Bagged "herb" or "Mediterranean" mixes are usually fine for bigleaf hydrangea 'nikko blue', but most standard composts need cutting hard with grit. The DIY ratio above is cheap and exactly right.
How often should I refresh the soil for bigleaf hydrangea 'nikko blue'?
A gritty mix barely breaks down, so bigleaf hydrangea 'nikko blue' needs little repotting — refresh the top layer and the grit every couple of years rather than potting on aggressively. Sharp drainage is everything: a terracotta pot with a big hole, gritty mix and never a saucer left full. Raised beds suit these herbs outdoors for the same reason.
Keep reading
- Bigleaf Hydrangea 'Nikko Blue' care — the full brief (light, water, humidity, problems, pet safety)
- How often to water bigleaf hydrangea 'nikko blue' — the schedule the mix feeds into
- Repotting bigleaf hydrangea 'nikko blue' — when and how to refresh the mix
- Soil pH guide — test it and adjust it safely
- Overwatered plant — signs and recovery
- Root rot — how the wrong soil starts it, and how to save the plant
- Should I water my plant? The simple check first
- Best soil for peace lily
- Best soil for bird of paradise
- Best soil for hoya
- All 1284 soil and potting-mix guides in the Growli library