HELP! me with my macrophylla

Discussion in 'Woody Plants' started by The Nut, Jun 25, 2008.

  1. The Nut

    The Nut Member

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    Hi
    I have a Hydrangea macrophylla, thats all it says on the box so to speak. Its just starting to bloom and has blue flowers which I want to stay blue. However I intend growing it in a container and want to know do I have to use a special kind of compost to keep it blue or do I just use the regular stuff?
    Thanks in advance
    Nut
     
  2. Ron B

    Ron B Paragon of Plants 10 Years

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    Depends on what's in the regular stuff.
     
  3. The Nut

    The Nut Member

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    The stuff that says "compost suitable for containers" I will go read the bag when its stopped raining or when I have built my Ark, whichever comes first. Dont hold your breath Ron as its raining cats and dogs here..... please dont say "watch out for the poodles"
    We only seem to have 2 kinds of compost the regular kind and the kind for Azaleas. Are there more than that?
    Nut
     
  4. Ron B

    Ron B Paragon of Plants 10 Years

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    The kind for the azaleas should be suitable.
     
  5. The Nut

    The Nut Member

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    Thks Ron. Will that keep it blue? Also its just coming into flower, do I repot it now or leave it til next year. Sorry in advance can you tell im new at all this?
    P.S can you send some sun plz?
     
  6. Silver surfer

    Silver surfer Generous Contributor 10 Years

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    I may be wrong, but I thought to get really blue flowers you needed acid soil /Ericaceous compost. Pink flowers come with alkaline soil (ph above 5.5)
    It is all to do with the aluminium ions in the soil. White flowered hydgrangeas are not affected and stay white.

    This link says all I am struggling to say!!!!
    http://www.foreverhydrangea.com/PDFs/How did Your Hydrangeas Bloom this Year.pdf
    Page 4.
     
    Last edited: Jun 28, 2008
  7. The Nut

    The Nut Member

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    Thks Luddite
    I have purchased the right compost and will be re potting it this weekend rain permitting..
    Regards
     
  8. growest

    growest Active Member 10 Years

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    Just to really beat this topic to death...:-)

    The aluminum is what produces the blue colour, and regular ericaceous/acid loving potting soil won't likely have enough aluminum in it despite the "correct" pH reading. I found this out growing many hydrangeas in the "backyard nursery" here...always flowering pink no matter how much peat moss or other pH tweaking of the soiless container mix. Pink is like the "default" colour of the flowers, and the blue pigment (evidently some aluminum compound) has to be specially created in the plant to "paint" over that pink background.

    In the UK, you may have John Innes style potting soils, which still actually have real "soil" included in them...combined with low pH these could work. Otherwise, some aluminum must be added...either from the aluminum sulphate which is highly soluble so works reliably, or with some other aluminum containing material like ordinary garden soil or, my favorite, rock dust which is sold for horticultural purposes.

    Interesting what the linked article mentioned about phosphorus...I use osmocote which is comparatively low in P, but some people do fertilize with esp. the liquid fertilizers like 20-20-20 which I can see interfering with this aluminum situation.
     
  9. The Nut

    The Nut Member

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    Thks growest and GULP! I never realised this gardening thing got so technical. I will try the John Innes I think and see what happends.
    Regards Confused in the UK
     
  10. Ron B

    Ron B Paragon of Plants 10 Years

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    Having endeavoured to see that the soil is acid and that it contains available aluminum, attention must also be paid to the type of fertilizer used. The balance of chemicals in the soil is critical for hydrangea flower colour. Still considering the case of blue flowers, a fertilizer low in phosphorus and high in potassium is needed, while the nitrogen content should be in the form of nitrates rather than ammonium. An NPK ratio of 25/5/30 is recommended. Superphosphates should be avoided, and little if any bone-meal used in planting.

    --Lawson-Hall/Rothera, Hydrangeas - A Gardener's Guide (Timber Press)
     
  11. Silver surfer

    Silver surfer Generous Contributor 10 Years

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    The Nut...Don't just stop at an ordinary blue Hydrangea. Try the white flowered Hydrangea quercifolia. Stunning flowers , interesting leaf shape and super autumn colour. No problem with these as to which colour flower you may get!!!
     

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  12. Ron B

    Ron B Paragon of Plants 10 Years

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    I much prefer the double 'Snowflake', probably what is shown on the left.
     
  13. Silver surfer

    Silver surfer Generous Contributor 10 Years

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    Ron . I agree. Names are on pics if you touch them. You got it id correctly as H.Q. Snowflake.
     
  14. The Nut

    The Nut Member

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    Would I get publicly flogged if I just bought plastic ones and shoved them in a pot :) JOKING!!!!
    I have decided to go with the flow, get what I like the look at and see what happens.
    Thks for the help
     

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