Rhododendron - Has John Innes #2 caused Yellow leaves

Newbie alert! I suspect that in using John Innes #2 in my beds, that I have upset my soil and my rhododendrons are now going lime green/ yellow... Firstly, does it sound likely that the John Innes #2 would actually cause this, and secondly can I now just buy Ericaceous and mix this in and around it, or must i do something more drastic to improve things? I read about putting a cup of vinegar in a gallon of water to create more acid soil. Would this be useful short term or just be useless? Thanks

 

Very unlikely that J.I. No 2 would have been Ericaceous (unless it said so on the packet). Sorry.

is your soil acidic? e.g. are there Rhododendrons and Azlaeas in gardens all around you?

yes = use some chelated iron, and Sulphur chips / similar to lower the pH. Dunno about your vinegar suggestion, might be a bit of a "shock".

No = None of that is going to work. Sorryx2.

You could try, but IMHO it will just end in disappointment, I wouldn't bother. People go to enormous length to have isolated, raised, acid-soil beds for Rhodies, I've never seen any looking like they are in the peak of health 10 years later ...

Just buy some that you are certain use the "Inkarho" lime tolerant rootstock, give them some peat to help them. Rhododendrons need plenty of water throughout the late-ish Summer when they are forming next year's flower buds.

My local garden centre is jammed packed full of Rhodie plants when they are looking their best, but there isn't any acid soil within driving distance from here, so the whole lot must die within a few years. There must be a huge market for lime-tolerant Rhododendrons in the UK, but they are not much found. The big sellers, like Millais, pay lip service to Inkarho - loads of plants listed on their website, which are out of stock most of the time, and expensive. I imported all mine direct from Germany to get around that ... shouldn't have needed to IMHO but there we go.

Sorry, no similar solution for Azaleas, Inkarho only available for Rhododendrons (that I know of)

 

I think it depends on how much JI you used.
I assume your natural soil is acidic, but the JI will contain lime.
You could try vinegar but don't overdo it.
Probably better to get some chelated iron and water that on.

 

Well there are other plants growing in other gardens around me quite well, but so too we're mine. It seems mine were good until I added a bag of John Innes #2 to the bed. I was trying to understand if simply adding some J.I. would have made the rhododendron get chlorosis ?. I just added a bag , thinking"any compost is good' ! I'm really just trying to figure out how I 'get back" to the acid soils i seem to have lost.. Will adding on top a bag of Ericaceous be useful or useless? I also read about Sequestrene _ is this the same as chelated iron?

 

Also, I haven't tested the soil as yet... Have soft water too in the area so guess that is good for rhododendron.

 

If you are on acid soil then I too would not have expects a dramatic reaction from just a top dressing. Soil test would help of course

Can you take the top dressing back off? That will stop any more Lime leaching from that into lower soil

I would go with Chelated Iron (yup, Sequestrene is the same stuff) liquid application as being the "fastest fix"

Rainwater would be best, if you have it, but yeah hard water would be bad, so soft water should be fine.

I have hard water, but I put it on my Ericaeous plants in summer after stored rainwater runs out 'coz any water is better than no water, so not something to worry about too much, but giving hard / tap water "all the time" is not great. Plants in the ground will get plenty of rain of course, so that would be much more relevant for anything in a pot where it gets nearly all its water from The Gardener

 

OK, if you are right I thought the same too , but have zero experience so couldn't state for sure! I suspect I am in acid soil, but will try and get some sort of kit online during lockdown to test.... Also, it's not so much of a top dressing anymore. I mixed it in... I think I'll go with the iron, and maybe throw in a bag of ericacacous to try and get back to where I was.... Thanks!

 

I've used the vinegar trick on carnivorous plants, it does work if you have trouble getting hold of iron at the moment.
Not sure, but don't get sulphate of iron, don't think it does the job in the same way as chelated.

As a side line, I throw all my apple "drops" under my rhody and camellias obviously don't look good but they do make the soil more acidic.

 

Great ideas, think firstly I'll get this chelated/ Sequestrene iron...