Hydrangea soil type – it matters more than you think

Hydrangea soil type – it matters more than you think

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What soil do hydrangeas like?

The best soil for Hydrangeas is a rich, well-drained, moist soil all the time. The water level requirements are a bit tricky insofar as they require moist soil at all times, but not wet. As a result of these moisture requirements, they thrive in areas that receive morning sunlight and then afternoon shade. Shadier areas keep the soil cool which helps retain moisture.

Mop head hydrangea pot grown
Mop head hydrangea pot grown


Hydrangeas are quick to tell you if there is a water issue. If they are not getting enough, their leaves will wilt immediately. If left unchecked, the blooms will droop too. This is a common problem when grown in pots, especially on very warm days.

When it is your first growing season, you want to water regularly to keep the soil moist. All-purpose fertilizers can be added to keep the plants healthy. If the blooms are sparse, a higher phosphorus fertilizer will aid in bud and bloom growth by way of improving root health and photosynthesis.

Soil Drainage

When you make changes to the soil, remember that hydrangeas require a humus-rich soil that is well drained. Adding loam or sand will help keep drainage at optimum levels. Clay soils retain too much water. If you have a particularly heavy soil you can add compost regularly or organic matter to help improve the soil quality.

Compost aids in drainage but it also feeds your hydrangeas. Peat moss is another option for drainage improvement. If using peat moss, add enough to bring the ratio in your garden to 80% soil and 20% peat moss.

Do hydrangeas need ericaceous compost?

Soil Chemistry and Color

The most commonly grown varieties of hydrangeas are the bigleaf varieties. There are others which produce white flowers, or white going on pink blooms. The quintessential blooms, however, are the bright pink, purple, and blue varieties of bigleaf hydrangeas. These varieties require the same soil/water parameters, but you can change the pH of the soil to control flower color which is where ericaceous compost comes in, basically, ericaceous compost will help turn flowers blue or retain their blue colour as its more acidic.

Getting Alkaline Soil

If you are growing bigleaf varieties and you want to make the blooms pink, you will need to sweeten the soil by making it more alkaline.

It is best to test and change the soil before you plant the hydrangeas if possible. There are soil pH kits you can purchase online and conduct at home.

Neutral is considered 7.0, with higher numbers considered alkaline and lower numbers considered acidic.

Pink blooms need a pH of 6.0 or higher. To make the soil more alkaline you can add lime sulfur to it or a high phosphorus fertilizer which will stop the plant from absorbing aluminium.

Getting Acidic Soil

If you want blue blooms, you can change the acidity with a soil acidifier, just by following the instructions on the package. You can opt for a gradual change by using acidic organic mulch from pine bark or pine needles too.

Note: If you have very high alkalinity in your soil, you may have a hard time getting blue blooms because high levels of alkalinity will typically lock up an aluminium in the soil preventing it from reaching your plant. In these situations, you are better off enjoying the beautiful pink blooms you have grown.

Be sure to regularly test the pH of the soil as you are undergoing these processes just to make sure you have reached the level changes you prefer. Know that soil will always return to its natural levels, so if you are changing the pH one year, you will have to do it each subsequent year in order to maintain the color you prefer.

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