Bringing a Hydrangea back to blue again

[amandaandherveg]

I'm a hydrangea novice but a lovely blue specimen caught my eye a couple of months ago and I took it home. It was in a small pot so I potted it on, unfortunately I used regular compost and now the poor thing is an icky, mucky browny pink.

Is there anyway to rectify my error and bring it back to it's former glory?

[Jeanied]

From memory you can use sequestrene to acidify the compost. Now someone will be along to say it is banned. I have also used spent coffee grounds but that is me being mean in throwing what looks like a useful substance away!

[Gearoid]

Re-pot it into an ericaceous compost which will help make it blue in future, but not this year. You can also add some "bluing powder" (aluminum sulfate) to the soil. I've tried throwing used tea bags around the base too, but they just end up a muddy purple colour.

[amandaandherveg]

Thanks folks.

When I remove it from it's pot should I wash off any surplus compost before repotting it in ericaceous?

[Tattie-muncher]

We bought one a wee while ago, and planted it in the garden, our soil is very sandy, so we added plenty of mpc with some Vitax bonemeal for good measure, and it appears to be working as its coming on a real treat

[bearded bloke]

Have a word with a scrappie & get hold of a few short pieces of aluminium & push them into the soil around the base of the plant roughly below the outer leafline,

[bearded bloke]

Bit of Googling & found .......

Flower color in H. macrophylla is dependent on cultivar and aluminum availability. Aluminum is necessary to produce the blue pigment for which bigleaf hydrangea is noted. Most garden soils have adequate aluminum, but the aluminum will not be available to the plant if the soil pH is high. For most bigleaf hydrangea cultivars, blue flowers will be produced in acidic soil (pH 5.5 and lower), whereas neutral to alkaline soils (pH 6.5 and higher) will usually produce pink flowers. Between pH 5.5 and pH 6.5, the flowers will be purple (see image at left) or a mixture of blue and pink flowers will be found on the same plant.

[dexterdoglancashire]

Useful thread and information guys and gals, as Dexter's Aunty Margaret has asked me to buy her one to plant in her front garden - her soil is mainly sand (does that make sense) so the above tips are very useful. Many thanks