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Removing all leaves on rhododendron?

Posted by marycontrary z6aCA (My Page) on
Mon, May 1, 06 at 14:40

I have a rhododendron that may have root rot. The leaves have all wilted and turned under. I read on the Am. Rhododendron site that with root rot the roots are "mushy" I dug up the plant carefully, and the roots looked fine, so I dug a wider deeper hole while soaking the plant and then added pebbles to the bottom--then mixed peat moss, good garden soil from another spot and potting mix and replanted the Rhodie. Now I wonder if leaving all these wilted leaves will just make it harder for the plant to try and recover, but I am totally inexperienced, so need advice, as to whether removing all the leaves will kill the plant completely. Thank you for any help.

marycontrary


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RE: Removing all leaves on rhododendron?

Root rot is fatal. What you do with the leaves won't matter.

Plants wilt and die slowly when their roots become blocked. There are two causes of this:

Root strangulation. This is best prevented by proper root pruning when planting. If the plant is not too far gone, it might be rescued by digging and removing the soil. Then cutting any circling roots that may be strangling other roots. The roots need to be opened up. On larger plants, some of the top must be removed to compensate for the weak state of the roots. Any time the roots are exposed, they must be kept moistened. Roots that dry out will die.

Phytophthora crown rot or wilt. This root rot is the major killer of rhododendrons and azaleas. It develops when roots are growing in wet conditions. The rot is more prevalent in warm summer conditions. Plants infected with crown rot caused by the fungi Phytophthora have roots which become clogged with brown fungi internally. The roots get blocked and the plant wilts and dies. There is not much of any cure for crown rot. Some varieties of rhododendrons are vulnerable (Chionoides, Catawbiense Album, Nova Zembla) and some are resistant (Roseum Elegans, Scintillation, PJM). Sphagnum moss and bark dust combined with good drainage seem to prevent crown rot, but do not cure it.

Wilt and slow death can also be caused by juglone poisoning from black walnut or butternut trees.

Plants wilt and die suddenly is usually caused by roots which are girdled by larvae of the Black Vine Weevil or Strawberry Root Weevil. Adult weevils feed on the leaves at night. Specimens may be collected at night for identification. The major damage is caused by weevil larvae which girdle the roots and kill the plant. Larvacidal drenches may be used to kill them but are of limited effectiveness. Foliar sprays are very effective at controlling adult weevils when leaf notching starts. Foliar sprays must be repeated until no adults emerge.

Entire portions of a plant die if a borer is in a branch. Borers only affect the portion of the plant away from the roots from the borer. If the borer is in the main trunk, then the entire plant will wilt and die. The plant can be save by cutting off the area with the borer and letting the plant regenerate from the roots.


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