Hydrangea Leaves Turning Yellow with Green Veins

I have two climbing Hydrangeas.
In two corners of our small garden (on north facing fence).

One of them has developed yellow with green veins (second picture) while the other seems fine (first picture).

At first I though it was drought related as it seemed to start during the worst of the summer heatwave - and only the one that gets most sun started turning yellow.
But even after a lot of recent rain there has been no improvement.

I than realized that it is actually getting worse and that the leaves are turning yellow but had green veins.

I believe this might be 'Chlorosis' ... due to iron deficiency (web search).

Can anyone confirm this looking at the pictures?
Why would only one of the plants have the deficiency?
Any advice on best cure?

Thanks

 

Certainly looks like chlorosis , Maybe one has hit a chalky deposit.

How big is it?

Get some Sequestrene or chelated iron and water a gallon or two around the base, it should sort it out, but often not immediately, takes a few weeks.

 

Tanks for the reply Pete,
The plant is about 2m x 3m. (pic attached)
I will try the Sequestrene or chelated iron.

 

Looks big, you will need to make sure it reaches the root area and doesn't just run off.

 

Its now been 2 months and an entire box of 'Wiko sulphate of iron' and no improvement.
Any idea if 'Wiko sulphate of iron' is no good - or what better brand to try?
Or might there be a different problem?
Thanks.

 

@j-Dubs
If you've used 1.5 kg of Iron sulphate on the one plant then you've overdone it a bit. The instructions say 35g/sqm a couple of times a season, so there should be enough in the soil for the next few years.
Did you water it in after application? If not with the dry weather we've had it probably hasn't reached the roots yet.
Given that climbing hydrangeas are deciduous I'd wait until the new growth in the spring and see what that looks like.
Sequestrene and chelated iron have the advantage that they are in a form more easily taken up by the plant and can be applied as a spray to the leaves.

 

Sulphate of iron is not the right stuff, and I agree with Nigel you have seriously over done it if you have used the whole box.

Iron is considered a trace element, so although the plant needs it to grow well it really only needs it is smallish quatities.

I also agree it getting too late to do much now and best to wait until spring and seeing how things go then.

 

I would check the soil pH using a soil pH kit and also research for a magnesium deficiency if two months of amending for iron deficiency had no results: Nutrient deficiencies / RHS Gardening

 

Thanks for all the input.

The 'Wiko sulphate of iron' was the only iron deficiency supplement I could find around here.
You (Pete) say 'Sulphate of iron is not the right stuff' but it says on the box that it is designed to solve exactly the problem (I think) I have. So I don't understand...

I did water in somewhat and there was plenty of rain since to get the product down into the ground but it was not clear how wide an area I should cover so at first I was very conservative.
After a couple of weeks I decided I had probably not applied enough and had another go.

Seeing no improvement at all after a few weeks I decided that the 'Sulphate of Iron' can't have been reaching the roots.
The plant is growing right next to a brick patio area - so half of the roots must be underneath the slab. I thought more 'Sulphate of Iron' might be needed to get it right under there.
With the plants looking worse and worse - rather than getting any better - in fear for the plant and a little frustration - I applied another load.
Hopefully the 'over ironing' wont kill everything off!

I have also noticed that the previously healthy plant is now also showing the same signs.

I will wait till the spring (with fingers crossed I haven't made things worse) and also try to find a soil pH kit - and check for a magnesium deficiency if you think that might be an issue (too).

Are there any particular brands of 'Sequestrene and chelated iron' you can recommend.
Where can I buy them?

Thanks again.

 

Chelated iron or sequestrene works better than iron sulphate.
Plants growing in alkaline conditions find taking up iron difficult, but in the chelated form it makes it more easily available to the plant.

I still think its too late in the season now to do much the plant will be going dormant for the winter soon.
Chempak Sequestered Iron Magnesium & Manganese 250g

 

Be careful with the pH results as the iron sulphate will have acidified the soil locally and temporarily.
Note the Chempak product also contains magnesium so if you use this product you will deal with both potential problems.
I would wait until growth is well underway next spring and then see if treatment is needed.

 

Thanks again for all the input.
I will hold off till the new growth starts in spring.