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I was given a beautiful pale blue hydrangea for mothers day which I potted up and it promptly turned purple. I don't particularly like them but feel I should continue with it and wonder if I should use another type of compost (which?) or use that liquid stuff that changes it blue. I would rather keep it in a pot due to lack of garden space.



This has confused me a little, it,s usually the pink ones that turn purple if they,re grown in an acid soil, but if you wanted to keep it blue I would plant it in ericaceous compost, or give it a dose of aluminium sulphate, or sequestrene every year, Derek.

12 Aug, 2012


Well it was a beautiful pale blue and I assume it was the compost I used which I didn't even think about and it turned a ghastly purple colour within weeks. I have cut all the flowers off (I know they are supposed to stay on to protect the plant during the winter) and its doing very well health wise. I have something in the garden shed to water in so I might try repotting it and using that. Thanks for your input.

12 Aug, 2012


I,ve a big one in the garden with pinks and mauves, its the soil.....we were at a nt garden recently and different parts of the gardens had varying hydrangea colours.....some gorgeous blue in the acid areas and one amazing white, I think ( but am not sure) that whites the only one not affected by the type of soil

13 Aug, 2012


You should have planted in ericasious compost but you must have used a compost containing lime which locks up the magnesium and iron, hence the shrub is turning mauve and eventually red or pink. John Innes ericasious compost and watering with rain water if you are in a hard water area. As advised, if grown in a pot it will eventually wash away nutrients so you will have to add some regularly.

13 Aug, 2012


Thank you. I always use rainwater from my water butt and haven't used tap water since long before the hose pipe ban. I will have to get some John Innes. I don't particularly like hydrangeas - I've given one away and uprooted another. I still have 3 - white, pink and this mauve one. I only want to keep this as my daughter bought it for me.

13 Aug, 2012

How do I say thanks?

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