Soil & potting mix
Best soil for Hydrangea 'Endless Summer' (Hydrangea macrophylla 'Endless Summer')
Also called Endless Summer Hydrangea, Reblooming Hydrangea.
More about hydrangea 'endless summer'
About Hydrangea 'Endless Summer'
Hydrangea macrophylla 'Endless Summer' · also called Endless Summer Hydrangea, Reblooming Hydrangea · flowering
Endless Summer is a reblooming bigleaf hydrangea that flowers on both old and new wood, giving mophead blooms from early summer to autumn. Flower colour shifts with soil pH: blue in acidic soil, pink in alkaline. A deciduous shrub for partial shade and moist, rich soil, it forgives spring frost damage by reblooming.
Preferred mix: Moist, fertile, well-drained loam rich in organic matter
Watch for — Unwanted flower colour: Colour reflects soil pH and aluminium. Apply ericaceous feed or aluminium sulphate for blue, lime for pink; expect a gradual shift over seasons.
Why hydrangea 'endless summer' needs this mix
Hydrangea 'Endless Summer' is a true acid-lover — it physically cannot take up iron above about pH 5.5, so an ericaceous mix is not optional, it is survival.
- Hydrangea 'Endless Summer' has evolved on acidic, peaty ground and depends on soil fungi that only function in acid conditions — raise the pH and it starves even in "rich" soil.
- In a too-alkaline mix iron and manganese lock up chemically, so the youngest leaves yellow between green veins (lime-induced chlorosis) and the plant fades out.
- Its fine, shallow roots also want an open, free-draining structure, not a heavy clay or claggy compost.
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 hydrangea 'endless summer' struggles, and the damage often shows up weeks later as a watering problem. For this species specifically:
- Ordinary multipurpose or garden compost is far too alkaline for hydrangea 'endless summer' — expect classic yellowing, weak growth and a slow decline over a season or two.
- Hard tap water slowly pushes the pH up too, undoing a good mix; rainwater is strongly preferred for watering.
- Lime, mushroom compost or wood ash anywhere near this plant is actively harmful.
Planting hydrangea 'endless summer' in standard compost or limey garden soil. Without an acidic (ericaceous) medium it will yellow and fail no matter how well you water and feed it.
pH — does it matter for hydrangea 'endless summer'?
This is the whole game: Hydrangea 'Endless Summer' needs pH 4.5-5.5. Test it, use ericaceous compost (and an ericaceous feed), and water with rainwater where you can to keep the pH from creeping up.
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 ericaceous compost is the correct, easy base for hydrangea 'endless summer'; just open it up with bark and grit per the ratio above. Do not try to acidify ordinary compost by guesswork — it rarely holds.
Drainage and the pot
Containers are often easier than open ground because you control the pH completely. Use a pot with good drainage and an ericaceous mix; never let it sit waterlogged.
Top up or refresh the ericaceous mix yearly and test the pH each spring — it naturally drifts upward over time, especially if watered with tap water. When the time comes, our repotting guide for hydrangea 'endless summer' covers the timing and technique step by step.
Hydrangea 'Endless Summer' soil — frequently asked questions
What is the best soil mix for hydrangea 'endless summer'?
3 parts ericaceous (acidic) compost : 1 part composted pine bark or pine needles : 1 part perlite or coarse grit. Hydrangea 'Endless Summer' has evolved on acidic, peaty ground and depends on soil fungi that only function in acid conditions — raise the pH and it starves even in "rich" soil.
Can I use normal potting soil for hydrangea 'endless summer'?
Ordinary multipurpose or garden compost is far too alkaline for hydrangea 'endless summer' — expect classic yellowing, weak growth and a slow decline over a season or two. Bagged ericaceous compost is the correct, easy base for hydrangea 'endless summer'; just open it up with bark and grit per the ratio above. Do not try to acidify ordinary compost by guesswork — it rarely holds.
Does hydrangea 'endless summer' need a special pH?
This is the whole game: Hydrangea 'Endless Summer' needs pH 4.5-5.5. Test it, use ericaceous compost (and an ericaceous feed), and water with rainwater where you can to keep the pH from creeping up.
Should I buy a bagged mix or make my own for hydrangea 'endless summer'?
Bagged ericaceous compost is the correct, easy base for hydrangea 'endless summer'; just open it up with bark and grit per the ratio above. Do not try to acidify ordinary compost by guesswork — it rarely holds.
How often should I refresh the soil for hydrangea 'endless summer'?
Top up or refresh the ericaceous mix yearly and test the pH each spring — it naturally drifts upward over time, especially if watered with tap water. Containers are often easier than open ground because you control the pH completely. Use a pot with good drainage and an ericaceous mix; never let it sit waterlogged.
Keep reading
- Hydrangea 'Endless Summer' care — the full brief (light, water, humidity, problems, pet safety)
- How often to water hydrangea 'endless summer' — the schedule the mix feeds into
- Repotting hydrangea 'endless summer' — when and how to refresh the mix
- Soil pH guide — test it and adjust it safely
- Root rot — how the wrong soil starts it, and how to save the plant
- Underwatered plant — signs and how to rehydrate it
- Should I water my plant? The simple check first
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