rododendron sun burn

Discussion in 'Outdoor Gardening in the Pacific Northwest' started by barely, Mar 27, 2010.

  1. barely

    barely Member

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    Hello everyone,
    A long time ago I wrote about this same Rododendron plant and how it wouldn't bloom. Well now it's been blooming wonderfully but last summer she/he got sun burned and now has a lot of burnt leaves.

    My question is: Should I break/cut off those brown leaves or the stem of the burnt? There is no way of protecting this bush other than transplanting, which I am UNABLE to do (body barely able to tend to my few plants).
    Thanks for reading this!
     
  2. Liz

    Liz Well-Known Member 10 Years

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  3. barely

    barely Member

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    Thank you for your quick reply Liz
    Right now it's just a little to dark to check for bugs/insects on the leaves. Are they visible to the eye when I look at the leaf's underside? I need the old drug store glasses to read fine print so I am just wondering if I should take the magnifying glasses out with me.
     
  4. barely

    barely Member

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    Well I've done the white paper test and check the leaves for critters. Both tests came back negative. So I am going to keep calling the brown leaves as sun burned. Until we can figure it out as something else.

    Last year the Honey suckle plant next to the Rhododendron had little worm type critters that was cocooned in a web type surround. The leaf then would be curled around the worm/critter. My red maple had the same problems as well but it's a long way from the two other plants.
     
  5. Hartley Botanic

    Hartley Botanic Active Member

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    No need to prune. The burn would only be superficial to the leaves in question so it's not like you have to worry about anything 'spreading' through the plant :)
     
  6. chimera

    chimera Well-Known Member 10 Years

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    Barely, would you know it's name , just curious in regards to which Rhododendrons do alright in your climate ?
     
  7. barely

    barely Member

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    Sorry I do not have the tag that came with the plant. Therefore wouldn't have a clue as to which type it is. It was purchased in Vernon, BC which is about a two and a half hour drive, but I am guessing all of this part of British Columbia is zone 6. I am wondering if a picture would help?
     
  8. M. D. Vaden

    M. D. Vaden Active Member 10 Years

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    Do you fertilize it?

    Because I have noticed that quite a few fertilized Rhododendrons get bigger leaves, and tend to "burn" or brown more when the weather is warmest.

    If no major nutrient deficiencies exist, I'd prefer to have a Rhody with smaller, but greener leave all season.

    Sometimes they brown anyway. But there is that food for thought if it may help at all.

    : - )
     
  9. barely

    barely Member

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    Every spring my perennials are fertilized, and they all face south. The Honey suckle when in full bloom shades the hottest (west) sun.
     
  10. barely

    barely Member

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    More more thought. This is the first year of many that the leaves turned brown.
     
  11. M. D. Vaden

    M. D. Vaden Active Member 10 Years

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    Are the leaves brown all the way around?

    Or brown toward more light, and not so brown toward shade?

    Patchy?

    : - )
     
  12. chimera

    chimera Well-Known Member 10 Years

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    It may help, especially if in bloom.
     
  13. barely

    barely Member

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    I have pictures of the plant in bloom, but there are no brown leaves then. I would have to wait for bloomage to take one with.
     
  14. barely

    barely Member

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    I hope this works: viewing from the top; top area where the direct sun hits, front side (facing the south), and a quarter (picture a circle) on the west side (where there is NO shade yet).
    Does this help?
     
  15. barely

    barely Member

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    I think this shot is the clearest and as the "How to Attach" suggests using the original which was not adjusted. Please let me know if it worked.
     

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  16. Freyja

    Freyja Active Member

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    I think my 6yr old rhodo also got sun damage last summer -- I recently read that if you keep the plant better watered in the hot sun, this damage will not occur.

    Can anyone confirm this? Or is it possible that a rhodo will be damaged regardless from too harsh of sun? It's been in the same spot for 6 years, and this was the first year of damage.

    Thanks.
     
  17. dt-van

    dt-van Active Member 10 Years

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    My experience with sun burn on Rhodos and other broadleaf evergreens is that it generally happens in the winter rather than the summer. This is because the sun causes water to evaporate from the leaves but it cannot be replace from the soil because the ground is frozen. Here in Vancouver damage usually happens on very cold clear days when there is no snow cover to insulate the soil. I would expect winter burn to be even more of a problem in colder, sunnier Revelstoke.
    I have had great success by spraying the top surface of the leaves in late fall with an anti-dessicant spray called "Wilt-Pruf". This type of spray is often used to preserve wreaths and cut Christmas trees and is also good to reduce transplant shock on evergreen or deciduous shrubs. It's an organic waxy coating which doesn't hurt the plant and gradually wears off on its own. You could try using it for protection in the hottest part of summer also, but don't use it all year round.
    Adequate summer watering is important, but keeping a rhodo's roots wet in very hot summer weather has other risks. Hot wet soil (especially in pots) provides ideal conditions for soil blights like Phytophthera which can cause an entire plant to suddenly die.
     
  18. Liz

    Liz Well-Known Member 10 Years

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    Would'nt the spray cook the leaves in summer?
    Looking at the photo it sure does not look like what I know as sunburn. The leaves go really brown and crackly on the ends after a 40C day. We were getting a lot of that during the drought. This last 12 months with more rain every one is happy green and lots of leaves.
     
  19. janetdoyle

    janetdoyle Active Member 10 Years

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    I may have sunburn too! I have two dwarf relatively large-leaved rhodos, I'll get a picture and the variety in due course up here, but the leaves in the past year have been coming out ok as new leaves, then gradually developing a crispy sort of grey-brown edge at the tips. I stopped fertilizing as I thought it might be that, but the fertilizer should be long washed out by rains etc. by now. So, I am considering moving them to a shadier spot -- they get both morning and afternoon sunlight before the cherry trees over and beside them leaf out, and I think that has burned them. After my neighbour townhouse's tree leafs out the sun is screened, then mine also screens some early morning sun...

    Does anyone know if Kalmia, particularly the more dwarf varieties like 'Minuet' or 'Elf', can take this amount of sun? I see a lot on the market right now, and purchased an 'Elf' for a more dappled-shade environment... I could switch locations for them and add another Kalmia, if you think they can take the light. Or, put them in an entirely completely shady-all-day environment, not sure that would work...
     
  20. chimera

    chimera Well-Known Member 10 Years

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    Liz, I don't think it is a recent photo so it's not showing the sunburn, or whatever the problem is. Looks like it may be some kind of yak hybrid.
     
  21. janetdoyle

    janetdoyle Active Member 10 Years

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    These are my possible "sunburn" photos, referred to above. There is a bit of a root weevil munching problem, too, developing, as exist in other areas of my garden. These are dwarf variety larger-leaved rhodos, sold commonly last couple of years, pink, can't think of the name... they seem to grow and expand willingly enough but the leaves don't stay very free of these problems and I am contemplating moving the two plants to a shadier location. The sun reaches them morning and early afternoon until the nearby Kanzan cherry trees leaf out. Does anyone else think these are sunburned?
     

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  22. chimera

    chimera Well-Known Member 10 Years

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    Don't think so janet. More likely fertilizer problems, cold damage, root damage, girdling by weevils, drought, or drainage problems.
     
  23. Liz

    Liz Well-Known Member 10 Years

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    Yes my burn does not look like that it is a sudden thing after a bad heat wave (40+C north wind off central Aust.) . Crispy brown

    Liz
     
  24. chimera

    chimera Well-Known Member 10 Years

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    In the same family {Ericaceae} as Rhododendrons, but a different genus. They will take a lot of sun and seem to like constant moisture here. A mulch helps.
     
    Last edited: Apr 14, 2010
  25. chimera

    chimera Well-Known Member 10 Years

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    Barely, here is Rhododendron 'Seven Stars', a variety particularly susceptible to sunburn here in half shade with sun mid day.
     

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