Rhododendrons: Rhododendrons not blooming

Discussion in 'Ericaceae (rhododendrons, arbutus, etc.)' started by saulsa, May 1, 2006.

  1. saulsa

    saulsa Member

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    Hi all,

    This is my first post here, and I searched through the older posts, and didn't see anything that seems to fit.

    I live in the Seattle area, so a similar climate to BC. I have 5 big rhodies in my front yard that were planted by the previous owners (we moved in 7 years ago). I have noticed that this spring they 3 aren't blooming, and don't seem to even have buds. Two large plants in have a couple of white blooms at the very top, but don't seem to have any more buds. All of them have longer, sticky growths where the buds should be, and a few of these have already formed new leaves. They didn't bloom last spring either. They have dark pink/reddish blooms when they do bloom.

    So, should I snap off these non-bud growths the way I would deadhead them after they bloomed, even though they haven't bloomed? These are large plants (10 - 15 ft. high) , so could be pruned, as well, if that would help.

    They are healthy plants, so it could be they are too healthy, even though I don't usually fertilize them or do anything special to them.
    Thanks for any insight!

    Laura
     
  2. Ron B

    Ron B Paragon of Plants 10 Years

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    Flower buds form on ends of strongest, stoutest shoots. Anything that prevents heavy enough growth from developing interferes with bloom. Taking out terminal buds of existing "blind" shoots will only make bloom next year less likely, as terminal bud on central stout shoot will have been removed. Similarly, if these shrubs have been pruned back in recent years to reduce their height setting of flower buds will have been delayed by that.

    Otherwise, powdery mildew of rhododendron has been diminishing many specimens in the region for some years now, by infesting their leaves and causing them to drop prematurely. However, you said yours look good.
     
  3. Cathy W

    Cathy W Member

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    I second Ron. If they aren't looking too lanky or straggly, I would avoid pruning at all this year if you can help it and see if they set buds for next spring. Then, if you feel the need to trim them back next spring, I would prune right after blooming when you dead head.

    I made the horrific mistake of "shaping" my lovely deep red rhodies late in the season one year and blooming suffered for three years after that. With patience and some TLC, they are finally back to normal. I don't know long you have lived there, but if the previous owners cut them way back to enhance the curb appeal of the shrubbery, that may be the answer and patience is the solution.

    The other problem I have had with my rhodies is that in the fall, when we have had an early and long freeze and then a very warm spell a few weeks later, the rhodies have been confuised about the season. When that happens, the buds that were set for the following spring begin to open and then invariably, we get another deep freeze or snow, and that's the end of them. When this happens, they generally don't bloom as well if at all the following spring. I live in New England and our weather is so unpredictable, this happens too often, unfortuantely.

    One other thing.... Where I live, the soil varies greatly in its acidity/alkalinity even from one end of my yard to the other and I have found a pH and fertilizer tester to be invaluable. I feed with with a garden variety fertilizer that is formulated for rhodies and also add peat and a good dose of comcpost when I am cultivating and clearing in the spring. I try to keep the dirt around my rhodies at about 5.5. Water meters are easy to find but I got my pH/fertilizer meter on line through Burpees.

    Hope you have some blooms next spring,
    Cathy W.
     
  4. jumbojimmy

    jumbojimmy Active Member

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    i discovere a secret to make rhododendrons bloom - they need to have adequate sunlight during spring time.

    mines was growing in a pot and is positioned in a shady position. i had to move it to a sunny position just when winter has finished.

    also - shock. one of my pot was broken and having trouble getting this shrub out so i bang the pot on the concrete in order to get th shrub out and too my amazement it bloomed during spring time.
     
  5. Margaret

    Margaret Active Member 10 Years

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    A couple of my rhodos have the same problems and I was just about to post a question. After reading this I think that I probably pruned some of the buds off last year but I am also puzzled because some of the new buds which I took to be flower buds but which I now realise are leaves are growing from areas which still have bits of last year's flowers below the new growth so obviously I had not pruned these. The few flowers which are blooming now are on the top of the plant at a height of about eight foot.
    Thanks for the info. I will leave them alone this year and see what happens next.
    Margaret
     
  6. Ron B

    Ron B Paragon of Plants 10 Years

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    Some deadhead hybrid rhododendrons to promote regular heavy flowering, because it is normal for shoots that have flowered and been allowed to set seed to not flower again for awhile. Fruiting causing a break in the routine on apple trees is called biennial bearing. Plants have only so much energy and not all specimens (or kinds) can sustain heavy annual production.
     
  7. Margaret

    Margaret Active Member 10 Years

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    Thanks Ron. Makes sense. Am I correct in thinking that I should deadhead all the flowers immediately after they have finished? If so I will have to get an extension to my long poled pruner! I don't know which varieties the rhodos are.
    Margaret
     
  8. Ron B

    Ron B Paragon of Plants 10 Years

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    Judging from flower color description you may have a little thicket of Rhododendron ponticum planted there originally as rootstock for hybrid rhododendrons, before growing rhododendrons from cuttings became common. Many older rhododendron plantings down here consist at least partly of such rootstock sprouts. Often the forms used produce comparatively unattractive specimens of tangled growth, and of course the coloring of the flowers of this species is not to everyone's taste either. If this is the case and it were my garden I would saw these down, remove the stumps and use the space for other plants.

    Or you may have examples of any of various common hybrids of this species (or others of vigorous growth and somewhat glaring flower colors). In either case I would not fuss with them too much, would probably even remove them if it were my place.
     

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