Rhododendrons: Rh. macrophyllum

Discussion in 'Ericaceae (rhododendrons, arbutus, etc.)' started by munroc, May 1, 2005.

  1. munroc

    munroc Member

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    Burnaby, BC
    I have a little rhododendron macrophyllum, but it isn't doing much more than staying alive. It's only about 8" tall, and I've had it for about three years. It was first planted in full sun for a year, and since has been put in the back of a border in semi-shade. I've tried to leave it alone, figuring it's a native, it'll do okay. In the spring it puts out new leaves, but then they seem to droop, and no flower buds. The soil in my yard is pretty good, and I routinely add compost.

    Should I be paying more attention to it? - giving it extra fertilizer and lots of water? Am I expecting too much too early?


    Last edited by a moderator: May 2, 2005
  2. Newt

    Newt Well-Known Member 10 Years

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    Maryland USA zone 7
    Hi Munroc,

    From what I've read, this is a shallow rooted plant that doesn't need alot of nitrogen. Could it be possible that you have it planted too deeply? Take a look here, but keep in mind that you have moved it, so it may take more time to settle in. The rule of thumb after planting is the first year they sleep, the second year they creep and the third year they leap. Scroll down to 'Site Characteristics'.

  3. Ron B

    Ron B Paragon of Plants 10 Years

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    WA USA (Z8)
    Good rooting out of healthy stock takes place the first fall after planting. There is no reason for top growth to take 3 years to become noticeably more rapid.
  4. Chris Klapwijk

    Chris Klapwijk Active Member 10 Years

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    Black Ceek, B.C., Canada
    Rhododendron macrophyllum is native to our region and may be found in Manning Park and in several locations on Vancouver Island. However, DNA testing of one of the Vancouver Island groupings turned up a suspicious lack of variability suggesting that stand may have been deliberately planted.

    R. macrophyllum is slow growing as a juvenile and known for its poor root structure when grown from seed, but it is one of the more drought-resistant species, so giving it lots of water may only serve to complicate matters.
    Ascertain your soil is fairly acidic, plant in dappled shade, keep moist, not wet, apply an inch or two of mulch to keep the roots cool and fertilize if you must, if your soil is as good as you say it is, you probably won't need to.

    We've had better success with grafted specimens of R. macrophyllum. We have some plants started from seed about 10 years ago and none are more than 25cm. tall. I grafted a single truss, given to me by the late Harold Johnson, onto a R. 'Cunningham's White' around the same time and that plant is now about 2.5m tall! (see attached image, plant in bloom at time of writing)

    For more on rhododendron cultivation, see Harold Greer's articles on Rhododendron Basics

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