Changing hydrangea colour

My grandma used to put the dregs from the tea pot (with real tea leaves!) on her hydrangeas to change the colour

Thank you all for such illuminating replies. Do appreciate them.
I’ll take up all your tips and see what occurs next Spring.
Cheers

Just a little reminder that hydrangeas contain cyanogenic glycosides, with higher concentrations found in the leaves and flowers. When ingested by pets, it can cause vomiting, diarrhea and lethargy.

I used to have many beautiful hydrangeas which were always blue. We had a clay soil and I wondered if it was that. We had lovely roses too.

We have bought a few blue hydrangeas over the years and although we have used the stuff from the garden centre to keep them blue they have always reverted to pink, so now we give up and when we buy new ones we either buy white ones or a really dark ruby red which is stunning

There are some hydrangeas that won't change colour however much you change the soil acidity so you need to check first to ensure you are not wasting your time!

Do the same tips apply to hollyhocks, please? I have had the most magnificent multi coloured display for years and now, for the last two years, they're still resplendent but all white. Help?

I used to have a huge one in my old garden and it had pink and blue flowers on the same plant. No idea why

Message withdrawn at poster's request.

Just use the Hydrangea Blue powder/ granules from the garden centre or buy online, it’s very cheap and effective.

We have two blues/pink hydrangeas in the front garden - one a cutting from the other and two white ones that I was given as a birthday present a while back, The white ones are huge this year.

My granny used to put rusty nails in the ground around it

Agree with Bobdoesit. In the 70s when we had nappy buckets, (yuk) I regularly emptied the bucket onto the hydrangea just outside the backdoor. It was certainly blue!

When I was a little girl my dad used to empty the guzunders (chamber pots!) on to the soil around his hydrangeas. He always swore it worked!

I have 2 in the same bed - one blue the other pink. They are well established & have been this way right from the start. I have never figured out why!

Hydrangeas are blue when grown on chalk soil or similar. In Sussex where I grew up all the hydrangeas were blue
Here in Somerset they are pink.
I can't say anything about the things garden centres sell but they are probably cheaper than moving :-)

I have a big hydrangea which has both pink and blue flowers. I’ve never done anything to change it so it must be something in the soil. Most hydrangeas are naturally pink and I think rusty nails, or similar in the soil are the reason they turn blue. I think it’s easier to change the paler pink ones than the darker ones.

Don't know much about gardening but the colour must be to do with rhe soil as I have a very old hydrangea bush which is half blue and half pink flowers! It is only cut back after winter frosts then completely neglected!!

Old nails, any size nails will do,( not finger nails ?) thrown into the soil, however, I don’t remember if it changes pink to blue or the other way around.

You can buy from a garden centre a hydrangea colourant. You can get pink to blue. The more you add thed bluer the hydrangea becomes. It will start off becoming pink/purple but if you keep going you will get blue. If you have alkaline soil you have pink and if your soil is acidic you get blue. If hydrangea is in a pot you can swap the soil for ericaeous compost ( get it at the garden centre about £3.99. Then you just keep topping it up. To get a shade of pink keep adding lime and for acidic keep adding iron/metal - hence people using rusty nails/pennies or vinegar (vinegar being acidic. The safer way though is to get some hydrangea colourant to put in the soil. It is better for the plant. Hydrangea colourant is about £2.99. White or green hydrangeas stay the colour you had when you bought the plant. The white flowers tend to be tinged with pink or blue though as the flower gets old and ready to die. When the flowers die leave them on the plant as it protects the plant going into winter. Then in Spring ,when frosts have passed, cut the flower heads off.
Hope this helps.

Or there’s this from t’internet
“To increase the acidity of your garden's soil, use vinegar! For each gallon of water in your watering can, add one cup of white distilled vinegar and pour on your hydrangeas. The acidity of the vinegar will turn your pink hydrangeas blue or keep your blue blooms from turning pink.”

I know absolutely nothing about gardening but I seem to remember something g about putting pennies in the soil....