Rhododentrons

This is a classic sign of chlorosis - an iron deficiency caused by the pH of soil being too high. Do you know the pH of your soil? It needs to be acid or ericaceous for Rhodos. You can try acidifying your soil by applying ericaceous plant food and mulching with ericaceous compost, But to be honest, in the long term you will be fighting a losing battle. I'm on neutral soil and I grow my Rhodos in large containers of ericaceous compo sunk into the ground. Hope this helps.

Hi jo and welcome to G O Y. As far as your Rhododendrons are concerned it sounds like they are suffering from Chlorosis an iron deficiency Rhodes like an acid soil of 4.5 to 6.0. spray with a chelated iron fertilizer and apply round the roots they should pick up. Best of luck give us a shout if i can help any more.