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Rhododendron Confusing Me

MTB79MTB79 Posts: 52

Hi,

I bought a generic rhododendron hybrid from B&Q back in March and planted it on my front garden, totally oblivious of its need for acidic soil by the way.

Anyway, in May it flowered a load of pretty white flowers which lasted for about two weeks which then died away.  The plant then proceeded to go on a growth spurt and roughly double in size in two months, but this is the weird bit... its now sprouting pink flowers.

Does anyone know why 1. it is seemingly flourishing in what as far as I know is not acidic soil? 2. Is it normal to flower twice? 3. Why the flowers are now pink when the first lot were white?

The whole gardening thing makes my head spin!

Thanks!

Posts

  • DovefromaboveDovefromabove Posts: 87,897

    Rhododendrons aren't quite as dependent on having acidic soil as azaleas and some other plants are, so if your soil is only marginally alkaline your plant may well be ok.

    It sounds to me as if the hybrid has been grafted onto another rhodo, possibly R. ponticum, and the flush of strong growth and pink (pinkish mauve?) flowers are coming from the rootstock.  If that's the case the R. ponticum will overtake the white flowered variety and grow into a massive shrub, totally unsuitable for a garden.  http://www.forestry.gov.uk/fr/rhododendroncontrol 

    Have a look and see if the new growth is coming from below the graft. 


    Gardening in Central Norfolk on improved gritty moraine over chalk ... free-draining.





  • YviestevieYviestevie Posts: 7,063

    No idea MTB79, I grow rhodos and my soil is neutral,  If any of the leaves go a bit yellowy (sometimes do, especially if I've had to water with tap water) I add a bit of ericaceous feed round the roots and it soon sorts itself out.  Rhodo flowers do change colour as they mature but not heard of totally different colours before.

    Hi from Kingswinford in the West Midlands
  • YviestevieYviestevie Posts: 7,063

    New someone would have the answerimage

    Hi from Kingswinford in the West Midlands
  • MTB79MTB79 Posts: 52

    Thanks for the replies.

    I will have a look when I get home from work, but so I know what I am looking for, can you tell me what I am looking for, as in graft and rootstock? Sorry for being dim.

    I have had no yellowing leaves yet, just an explosion of dark green ones.

    If it is an R.poniticum could I not just keep it regularly trimmed back or is there a root issue?

    Thanks again

  • MTB79MTB79 Posts: 52

    It would be a bit irresponsible for B&Q to sell a R.poniticum with this label wouldn't it?

    image

  • DovefromaboveDovefromabove Posts: 87,897

    Many rodos are routinely grafted onto R. ponticum, just as pears are grafted onto a wild quince and apples are grafted onto varied apple rootstocks - an explanation of the whys and wherefores of grafting here https://www.rhs.org.uk/advice/profile?PID=359 .  It is perfectly normal and shouldn't be a problem in normal circumstances. 

    The question is, why has the rootstock put on top growth and flowered (if that is indeed what has happened).  Has the graft been improperly performed or subsequently damaged, or has some damage been done to the rootstock below ground, which has stimulated growth?

    So that you know what you're looking for, this link should show a picture of the top growth of a named variety, grafted onto a rootstock  http://rhododendron.fr/dos23_e1.htm 

    Look for something like that, and see if there is single branch bearing the pink flowers, and identify where that branch is growing from. 


    Gardening in Central Norfolk on improved gritty moraine over chalk ... free-draining.





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