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Rose Of Sharon Buds Not Opening

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From: Ronald VorBroker
Palatine, IL
I have 12 different Althea (Rose of Sharon). Mostly tree form. For the last several years one of them has produced tons of buds but no flowers and last year a second one has shown the same problem. These affected plants are over 200 feet apart with 10 unaffected plants between them. Every body gets the same sun, water and fertility dance. Whatever is on them is sucking the buds dry and not affecting the leaves, stems or branches. It looks like little white fuzzy balls on the tips of the buds only. The white stuff does not move around. Every other part of the plant looks healthy. Nothing on the leaves, nodes, crotches, etc.. The buds do not turn yellow and drop off. The just stay there until late fall. I have dissected the buds and can find no evidence of any insect. Nothing is in the bud. I have tried every version of alcohol, soap concoction known to man. That gets rid of some but not all of the white stuff and 2 days later it is back. I have tried fungus sprays. I have tried insect sprays. I have sprayed the plant. I have sprayed the ground. I have not done a snake dance yet..... I can send you photos if it would help. I have talked to all of the garden centers in my area and shown them photos. They have been of no help. I know it is NOT mealy bugs.

Extension Message
From: Greg Stack
Extension Horticulturist
Extension Web Development
Without sample or photos I can only guess. It sounds like bud blast which is a form of botrytis. Many plants can get this conditions and when it happens flower buds remain unopened but they develop a brown, papery look to them. If this is the cause it is a fungal disease that is weather dependant for severity. The only way to try and deal with it is to spray before the buds appear with a fungicide to protect the buds. using something like maneb or mancozeb is suggested making several applications to protect the new buds.

From: Jean Rowan
Deep Gap, NC
This same thing happened to my Rose of Sharon shrubs this year. A lot of buds, very few opened. It seems that the insecticide on the buds would also affect the flowers and then the bees, butterflies and hummingbirds that gather nectar from the blooms would be poisoned. Also, the leaves on a few of mine are turning yellow. Are they dying?

From: ra ling
mashville, TN
Has anyone found anything to work on this problem? I have exactly the same problem as r VorBroker and Ms Rowan. TN extension service has not a clue. My brown buds are still attached. Bush is fine. I hate to loose all my Rose of Sharons. Disease eventually spread to all 9 of my bushes by the end of the year last year. They are now dormant at 22 degrees outside. Thank you for your attention.

Extension Message
From: Richard Hentschel
Extension Educator, Horticulture
DuPage/Kane/Kendall Unit
Bud drop can be caused by too much or too little soil moisture, and as Mr. Stack mentioned the disease we know as Botrytis, which we can treat. As noted in your description of the problem a disease will spread from one plant to the next all the way down the row, versus an environmental cause which would affect all the plants at the same time. Fungicides are only preventative and must be applied before the disease develops. In Illinois, fungicides currently label are products such as Captan, copper sulfate, chlorothalonil. Read the labels at your local garden center to be sure both the disease and plant are on the label before purchasing.

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