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Rhododendrons buds don't bloom

true_blue
13 years ago

Hi,

I planted a PJ Mezzit rhododendron in my zone 5 garden in Montreal in partial shade

3 year ago.

Last year only one side of the plant flowered. This spring it was doing fine, full of buds and then I noticed the leaves somewhat curved to the inside.

As weÂre having a rather dry spring, I gave it a good soaking.

The buds seemed to be ready to blossom but it now looks like stunted, as if the flowers have difficulty to open.

Furthermore I noticed that there are reddish brown blotches on the leaves.

And some of the branches are white whereas some others have a healthy apricot color.

Can you tell me if itÂs serious trouble or is there a way of saving it?

Thanks,

Bob

Comments (9)

  • luis_pr
    13 years ago

    I hate answering with more questions but I got the impression there may be several problems. I was wondering..... Is the side that does not bloom the one most affected by the cold winter winds? Do you notice any hair like sticks growing on the flower buds? How widespread is are the red-brown splotches? Can you post some pictures? For how long has the plant been under this drought that you mentioned (rhodies will abort flower buds if they are allowed to get "too" dry)? Have you noticed any pests on the leaves (above or below)?

  • true_blue
    Original Author
    13 years ago

    Hi Luis,
    Thanks for your response.
    I am going to post some pictures soon.
    Now for the questions:
    1) Is the side that does not bloom the one most affected by the cold winter winds?
    It could be. I never bothered to protect it, believing that being a city garden with fences around it won't be affected by cold winds. Maybe I should for next year.

    2) Do you notice any hair like sticks growing on the flower buds?

    3) How widespread is are the red-brown splotches?
    There are on some of the leaves.

    4) Can you post some pictures?
    I will. The link is below. Let me know if it works. It's on Picasa.

    5) For how long has the plant been under this drought that you mentioned (rhodies will abort flower buds if they are allowed to get "too" dry)?
    Well maybe a week or so. I am wondering if the heat wave we got in mid march did affect them. However a neighborÂs 6 rhodies were all in bloom this year. (his had winter protection and theyÂre in full sun). In Montreal we normally donÂt bother to water the plants, especially in spring.

    Have you noticed any pests on the leaves (above or below)?
    IÂve been checking the leaves all over and havenÂt seen anything.

    Here is a link that might be useful: Rhodo Pictures

  • rhodyman
    13 years ago

    Your plant looks good. The flowers look like they tried to open but were frozen back by a late frost. This is a fairly common problem with PJM. It is extremely hardy, but blooms so early that a late frost will nip the flowers.

    The flower buds are formed during the summer. A summer drought can affect flower bud production. A drought during the bloom season will cause problems, but any plant that is properly mulched will withstand several weeks of dry weather.

    Here is a link that might be useful: How to care for rhododendrons and azaleas.

  • true_blue
    Original Author
    13 years ago

    Thank you Rhodyman.

    Do you mean the white stems are normal and the blotches are common?

    What do I have to do with these frozen blooms, do I have to remove them?

  • true_blue
    Original Author
    13 years ago

    I took a couple of more pictures, I realized that one couldn't see the droopiness of the leaves from my other pictures.

    This has been going for the past week or so. Even after a good soaking!

    We had a fair amount of rain yesterday.

    Here is a link that might be useful: Rhodo Pictures

  • rhodyman
    13 years ago

    The white stems are caused by lichens which are harmless epiphytes.

    I don't have an explanation of the speckles in the leaves, but I don't know of a symptom of something bad that resembles that. Usually any spots visible from the top are just evidence of something obvious on the bottom. That is not true in your case. Yours may be a result of cellular frost damage.

    The curling of the leaves is unusual. I my be a result of the frost damage that is evident on other parts of the plant and related to the speckles.

    Your plants don't seem to have much mulch. Mulch is important. It provides protection to the roots from heat, cold and drought. It also decomposes and provides a gentle natural form of fertilization to the plants.

    The main enemy of rhododendrons is wet roots. Make sure your have good drainage and don't water if they are already moist.

    Good Luck!

  • true_blue
    Original Author
    13 years ago

    Hi Rhodyman,

    Thank you for your detailed response.

    From what I know the soil is well drained.
    I'll add some more mulch soon.

    One last question, do I have to remove the blooms and how is it done.

  • NHBabs z4b-5a NH
    13 years ago

    One way to delay flowering a bit is to plant them so that they are in shade in spring so that the snow melts more slowly and the ground stays cool longer.

    From Valley Forge chapter of the American Rhododendron Society:
    "Dead-heading: Removing the wilted trusses of large-leaf rhododendrons soon after blooming is beneficial for young plants, for energy is directed into vegetative growth rather than seed production. Cut or snap out the sticky seed-pod clusters above the new leaf buds, trying not to remove these buds."

    Here is a link that might be useful: planting and care of azaleas and rhododendrons

  • rhodyman
    13 years ago

    It is important to remove diseased material from the vicinity of a planting. This means removing dead material that harbors spores of fungal disease and dying material that contains eggs of insects. Dying portions of a plant should be cut off and removed. The ground should be cleaned of dead leaves or flower parts. Pruned parts should be removed.

    Deadheading flowers involves removing the structure left after blooming before seedpods form. A rhododendron or azalea flower is composed of several florets connected to the stem by a base that is easy to break. When deadheading just grab the flower near this base area and twist the flower sideways and break it off in this spongy area. Try not to break any of the buds that are around the base of the flower.

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    In general all dead or dying plant material may harbor disease and should be destroyed by incinerating or placing in a trash receptacle. Wilted flower petals can harbor fungi such as petal blight. Dead stems can harbor larva of borers. Dead leaves can harbor spores of harmful fungi. On healthy plants, deadheading is desirable but not necessary. [Photos by Steve Henning]

    Is deadheading necessary? If the blooms were healthy, and if the plant blooms well every year, and if you don't mind the look of the plant with the wilted blooms, then there is no reason to remove them.

    However, if the blooms were infected with petal blight, or if the plant doesn't have a good bud set or only has a good bud set every other year, or you don't like the look of the plant with the spent flowers on it, then remove them.

    On some varieties deadheading makes a difference, on some it doesn't matter at all. On most varieties, it will only make a small difference if any. Most gardeners would like to deadhead but few actually do.

    If you are getting petal blight, then deadheading is very important. All spent flowers should be destroyed. The best way is to toss them in the trash. Petal blight is a disease that hits some rhododendrons and azaleas that bloom later in the spring. It causes the flower to turn mushy before it naturally wilts. If you look closely it forms unsightly brown spots on the flowers.

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