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Rhododendron Leaves turning Black

Posted: September 6th, 2014, 4:41 pm
by Brod
I Noticed today that on My Rhododendron some of the leaves were Starting to turn Black, I wasn't sure what caused it so i figured someone on here might know.
It hasn't flowered this year But has been growing well and has lots of new shoots staring to appear. Some of the new leaves are also starting to go a burgundy colour too, Not sure if this is part of the same thing or Just what happens.
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Any Advise would be greatly appreciated :tu:

Re: Rhododendron Leaves turning Black

Posted: September 6th, 2014, 5:06 pm
by Bush bunny
Where are the black ones? They just look like darker green being the older ones. The lighter leaves appear to be new ones? But in doubt re-pot it, note its drainage. The only suggestion I can make if the leaves are indeed black, it is drowning. I'll enlarge the picture to make sure. :reading:

Re: Rhododendron Leaves turning Black

Posted: September 6th, 2014, 5:13 pm
by Bush bunny
I've enlarged the pics. Maybe more experienced bonsai-ers can make a comment. It could be a nutritional deficiency or have you sprayed it with something? I'm sure that someone will give you an answer, but black usually means to me anyway, I killed an avocado with it, is drainage. Or cold.

Re: Rhododendron Leaves turning Black

Posted: September 6th, 2014, 5:54 pm
by Brod
I have circled the leaves that are starting to turn black, its not the whole leaf just the end half.

Re: Rhododendron Leaves turning Black

Posted: September 6th, 2014, 6:07 pm
by alpineart
Hi Brod , mate mine were hit by frosts and have a burn ressembling these pics . My ground growing garden Azalea's are fine its only the bonsai trainers that are effected . I wouldn't be too worried as it certainly looks healthy enough . Time to fert with Azalea or Citrus food and a pinch of chelated iron helps with any yellowing .

Cheers .Alpineart

Re: Rhododendron Leaves turning Black

Posted: September 7th, 2014, 11:52 am
by Bush bunny
Maybe just pick that leaf off at its stalk. Quicker remedy, eh? :whistle:

Re: Rhododendron Leaves turning Black

Posted: September 7th, 2014, 5:13 pm
by treeman
If it's a sastuki it could be frost. Usually though there are two main reasons for blackening leaf tips. Too much fertilizer or too much water. They are last years/season's leaves so I would not worry too much but if it happens again, I would check out the above 2 possibilities.