Help with rhododendron disease

[Muddy42]

Pictures below of my Rhododendron Campylocarpum. Normally it has yellow flowers.  For the last three years or so it has slowly wasted away.  It has very few leaves and those few that remain don't do well.  My working assumption is that it is some kind of fungal infection and I have treated it once so far (yesterday) with Triticonazole. I have also removed over-shading trees and branches and fed it some well rotted manure and a sprinkle of fertiliser.  I have ordered some Ericaceous feed also.

 

Any further diagnosis or advice would be gladly received!  Thanks in advance.

 

 

[openspaceman]

Looks like rust, are there spruce trees nearby?

[AJStrees]

+1 for rust. Have you raked off any dead leaves from beneath it? How long was it growing there happily?

[Muddy42]

24 minutes ago, openspaceman said:

Looks like rust, are there spruce trees nearby?

 

Thanks. The area is fairly open and mixed in terms of trees, there are single spruces 500m away and blocks of sitka spruce about 1/2 a mile away.

 

19 minutes ago, AJStrees said:

+1 for rust. Have you raked off any dead leaves from beneath it? How long was it growing there happily?

Happy to rake off dead leaves if you think that will make a difference.  It was growing healthily for about 30 years. It was quite rare when planted, but less so now.

 

Can you treat rust? I will google this also.

 

thanks both

 

 

[GarethM]

I thought rhododendron in anything other than a garden was usually treat with Extreme prejudice?.

 

In part due to it being poisonous and kills or outcompetes practically anything growing under it.

[Muddy42]

3 minutes ago, GarethM said:

I thought rhododendron in anything other than a garden was usually treat with Extreme prejudice?.

 

In part due to it being poisonous and kills or outcompetes practically anything growing under it.

 

Yes here in west Scotland, I spend a fair bit of time burning and killing the common rhododendron ponticum (grows like crazy, purple flowers) but nurturing the less common garden varieties, with are much less invasive.

 

Yes ponticum is poisonous and produces a mild narcotic smoke when burned I believed.  But I'm not afraid of it, nor do worry about over shading of the garden varieties.  Its taken 30+ years to grow 10 foot high!

[AJStrees]

I've had a couple of rhodos give up the ghost after the last couple of very dry spring/summers where I am. I would imagine the rhodo has been stressed more recently and as a result has contracted something such as the rust etc... Looks like its been in a fairly damp spot though based on the lichen, etc... growing on it. 

 

You could try giving it a good feed with something for rhodo's and see if that works. 👍

[Stere]

Id suggest coppice it right to the base you never know it might regenerate it.

 

 

 

 

 

 

 

Edited March 20, 2023 by Stere

[Muddy42]

47 minutes ago, AJStrees said:

I've had a couple of rhodos give up the ghost after the last couple of very dry spring/summers where I am. I would imagine the rhodo has been stressed more recently and as a result has contracted something such as the rust etc... Looks like its been in a fairly damp spot though based on the lichen, etc... growing on it. 

 

You could try giving it a good feed with something for rhodo's and see if that works. 👍

yes I currently plan to feed, remove the fallen leaves and give it a few courses of various garden fungacides. Thanks

 

36 minutes ago, Stere said:

 

[nepia]

Compost for rhodos and azaleas, not manure; the latter is too high in nitrogen.  And don't mulch it deep; it inhibits flowering of plants that have shallow roots.