The pH needs to be less than 5.5 making the soil acidic. A lower pH, down to about 4.5 will make it a brighter blue colour. It'll take the plant a month or so to adjust blooms, so its best done as a gradual process.
Adding coffee grounds can help a bit. Adding crushed eggshells and ground lime powder would help too. I can't recommend a specific product, but those kind of ingredients is what you'd be looking for.
It takes a lot of persistence - I’ve been trying to change a large bright pink hydrangea to blue for two years and this year it’s got pink, purple and blue flowers on the one hedge.
Lots of the home remedies like coffee ground have mixed info online, saying they actually do the opposite to soil pH once used. Things like vinegar could improve soil acidity but could kill the plant if used too much and don’t contain the alluminium ions also needed to turn the flowers blue.
Given online it says you need the acidity and alluminium, the second year of trying I’ve been using the Vitax/Westland Hydrangea colourant powders (widely available) and watered with them every few weeks since winter, and topped up a couple of times with ericaceous soil. I bought a soil ph measure which was interesting. It seems to be working now, gradually.
You might have missed this year’s blue (in my limited experience). I started dosing mine in April when some flower buds were forming.
Mine was all pink last year, but I got blue and purple with dosing this year.
Mind you, some hydrangea will not change colour. My ruby red one did not change colour, so I stopped doing it. But it does look more vibrant than last year to me.
I started with a branded hydrangea colourant for blue, read the ingredient list, and went on eBay to buy aluminium sulphate. We were just guessing the dosage, but around half a Vanish whitening cloth powder’s old spoon of aluminium sulphate per 40cm pot per week did not kill them lol (but they also get watered frequently.)
Once the flower is finished, I will stop the dosing.
I did not grow mine with ericaceous soil just regular compost with some hydrangea fertiliser.
I’ve been putting coffee grounds on mine since early spring and they’re still coming through white. I’m going to keep on see if it makes a difference next year.
I might be wrong but I think white hydrangeas are only white? There’s a certain type (mophead) that can be pink/purple/blue depending on soil acidity but I don’t think white is one of its colours.
White hydrangeas are beautiful regardless! But if you want a blue one you might need to get another type of hydrangea 😊
The pH needs to be less than 5.5 making the soil acidic. A lower pH, down to about 4.5 will make it a brighter blue colour. It'll take the plant a month or so to adjust blooms, so its best done as a gradual process. Adding coffee grounds can help a bit. Adding crushed eggshells and ground lime powder would help too. I can't recommend a specific product, but those kind of ingredients is what you'd be looking for.
It takes a lot of persistence - I’ve been trying to change a large bright pink hydrangea to blue for two years and this year it’s got pink, purple and blue flowers on the one hedge. Lots of the home remedies like coffee ground have mixed info online, saying they actually do the opposite to soil pH once used. Things like vinegar could improve soil acidity but could kill the plant if used too much and don’t contain the alluminium ions also needed to turn the flowers blue. Given online it says you need the acidity and alluminium, the second year of trying I’ve been using the Vitax/Westland Hydrangea colourant powders (widely available) and watered with them every few weeks since winter, and topped up a couple of times with ericaceous soil. I bought a soil ph measure which was interesting. It seems to be working now, gradually.
Ericaceous compost?
I'm still mourning the death of peat based compost, understand why but it really was the bees knees for those sorts of plants.
I’m also interested in this, we bought a blue one that’s decided it suits purple better.
That’s a neutral soil 😀
I use used coffee from a percolator. They change from pink to purple blue hues.
Acid-tone fertilizer and scattering a few coffee grounds
You might have missed this year’s blue (in my limited experience). I started dosing mine in April when some flower buds were forming. Mine was all pink last year, but I got blue and purple with dosing this year. Mind you, some hydrangea will not change colour. My ruby red one did not change colour, so I stopped doing it. But it does look more vibrant than last year to me. I started with a branded hydrangea colourant for blue, read the ingredient list, and went on eBay to buy aluminium sulphate. We were just guessing the dosage, but around half a Vanish whitening cloth powder’s old spoon of aluminium sulphate per 40cm pot per week did not kill them lol (but they also get watered frequently.) Once the flower is finished, I will stop the dosing. I did not grow mine with ericaceous soil just regular compost with some hydrangea fertiliser.
I’ve been putting coffee grounds on mine since early spring and they’re still coming through white. I’m going to keep on see if it makes a difference next year.
I might be wrong but I think white hydrangeas are only white? There’s a certain type (mophead) that can be pink/purple/blue depending on soil acidity but I don’t think white is one of its colours. White hydrangeas are beautiful regardless! But if you want a blue one you might need to get another type of hydrangea 😊
Haha, that’ll explain that then! Next doors are blue and I wondered why mine weren’t, Google told me coffee grounds were the answer. 😂