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amoc_gw

Rhododendron Olga

amoc
16 years ago

I have planted some Olga rhododendrons in two beds around my house. horticulturist made a plan for me and she liked them for some reason. They bloom beautifuly in early spring but after that, until about July they look very sad. Their old leaves from winter are dark and dry looking and the new leaves are slow to come in. The debris from the flowers is hanging on for a long time. I regret planting them there, now that I have to look at that mess so often..

Anyway, is there anyway I can help them look better? I did add fertilizer to the soil in the spring. One of them was almost decapitated by mistake, and on the one remaining branch it put out happy new growth very fast. Should I prune them? Fertilize more? Water more?

One of the clumps is in more shade than the other - it does not seem to make a big difference...

Thanks for any ideas,

Anda

Comments (3)

  • rhodyman
    16 years ago

    Don't water unless they look wilted in the morning. They are very sensitive and have indicators to tell you what they want. They will wilt in the heat of the day and that is normal, don't water. But if they are wilted in the morning water. To much water will kill them so only water when they need it.

    If the leaves turn yellow with green veins, it either needs more acidity or more iron.

    If the leaves are uniformly yellowish, it needs more nitrogen and magnesium sulfate (Epsom salt).

    Only prune them if they need it. It is too late to prune them now. They must only be pruned right after blooming or you will be pruning off next years flowers.

    Then can be deadheaded after blooming. This means removing the spend flowers by twisting the flower off in the spongy region just below the flower where it connects to the stem.

    The new leaves will soon cover the old spent flowers.

    In winter, this plant is covered with mahogany colored, small leaves which are bright green in summer. But just wait until spring comes, when it is transformed by numerous trusses of clear pink on every limb of the plant. ItÂs hardy and sun tolerant making it especially valued if you donÂt have much shade in your garden.

  • amoc
    Original Author
    16 years ago

    Thanks much for your advice. I will dedhead them next season, so they look cleaner. Looks like they are just fine.

    Now that you mention it, if i look closely at the leaves they are covered with small yellowish dots, giving an appearance of a lighter green leaf. Is that the nitrogen problem? My soil is poor, sandy, slightly acidic. But i gave them a slow release fertilizer for azaleas in spring. The box said it last 3-4 months. Maybe its time to feed them again.
    Thanks

  • rhodyman
    16 years ago

    I would not feed after mid summer. Your plants need to harden off in the fall and fertilizing can keep them from going dormant.

    Uniformly yellowish-green leaves is often symptomatic of a need for more nitrogen. This will be more noticeable in the full sun. However yellow spots can be symptoms of something different:

    Yellow mottling on the upper surface of leaves and black sooty mold and transparent insects on the bottom are symptoms of Azalea Whitefly (Pealius azaleae) and Rhododendron Whitefly (Dialeurodes chittendeni).

    Yellowing and dropping of leaves is normal toward the end of the second summer on the small-leaved lepidote rhododendrons such as Olga. These should have dense enough habit that this doesn't matter.

    Whitish specks on the upper surface of leaves and dark spots varnish-like on the bottom are symptoms of Rhododendron Lace Bugs, Stephanitis rhododendri, and Azalea Lace Bugs, Stephanitis pyrioides, small insects with transparent wings on under-surface of leaves. This insect hatches early in spring as the new foliage begins to mature and its numbers may build to damaging levels with successive generations. Lace bugs reach their peak in late summer and do their worst in sunny, exposed sites.

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