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The problem is powdery mildew, a fungal leaf disease that's been particularly bad this year on a lot of plants. The disease spores germinate best in high humidity or when its raining a lot, and then the disease itself takes off in hot, dry weather. That's exactly the weather recipe weve had this summer. Heres what Id do:
1.) Rake up and get rid of any leaves that have fallen. This removes future infection.
2.) Prune out one-third of the biggest, oldest shoots right to the ground. This will thin out overly dense growth and increase air flow through the plant, which will help dry the leaves and take away the dampness the spores need to germinate.
3.) Avoid fertilizer, especially ones high in nitrogen.
4.) Avoid watering it. Ninebarks are very drought-hardy once established. But if yours ever gets so dry that it starts to wilt (Heaven help everything at that point), water only the ground and never the leaves.
5.) Watch early next summer for any signs at all of new mildew. At that point, start spraying every 10 to 14 days with a fungicide. The most non-toxic approach is a homemade solution using an eighth of a teaspoon of baking soda and two or three drops of dish soap in a 16-ounce spray bottle filled with water and mixed well. A very low-impact commercial product is neem oil, available at garden centers under several brand names. You might also begin to see the pretty innocuous potassium bicarbonate showing up in catalogs and garden centers under such brand names as Remedy and Armicarb 100. If you want to haul out chemical controls, any of these control powdery mildew: triadimefon (Bayleton), propiconazole (Banner), triforine (Funginex) and thiophanate methyl with mancozeb. The key to any of these fungicides is getting it on early in the disease process and then using it regularly while conditions are ripe for mildew (which is most of the summer in our typically humid climate). Some people don't even wait for early signs. Theyll routinely spray from spring into fall.
If all that doesnt help, try cutting all of the branches right to the ground right after the plant blooms (next July). Remove any debris around the plant and put down a fresh coat of mulch. Hopefully the new growth will then be free of trouble. Get into a regular pruning routine of removing one third of the biggest, oldest shoots every summer right after bloom and then shortening the remaining branches to whatever height you like. This prevents overly dense growth and results in a completely new shrub every three years. If you still have trouble after that, its time to root-prune Diabolo and go with a different species, such as viburnum.
- George Weigel
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∙ 12y ago
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How do you cure powdery mildew on caragana?
Spraying powdery mildew with baking soda added to water does not work. Spray with "Garden Sulphur" or "Garden Copper", both in powder forms, as per package directions every 7 - 10 days. This is also effective for powdery mildew on roses.
Your rose bush has white powdwer on the leaves?
Sounds like mildew. Spray with a fungicide that should cure it unless its too far gone. If you think it is not recovering after a couple of weeks cut it back to the lowest bud,remove any foliage left,spray again and keep your fingers crossed.
How do you cure white birch bark?
To cure white birch bark, first remove the bark from the tree. Then, press the bark flat using a weight to hold it in position. Some people use books or metal weights to press the bark. Once it has dried for several days, the bark is cured for use.
What is in the gummamela bark that can cure dysmenorrhea?
nope it cannot, haha!
How did cartier cure scurvy?
he used white cedar bark and leaves
What is the cure for white spots on butternut squash leaves?
Most likely this is powdery mildew. Remove severely damaged leaves (do not compost). Weed and thin plants if necessary they need good light and air circulation. Water the base of the plant not the leaves. To treat use an organic fungicide spray, milk/water solution or a baking soda/water solution.
Why did tea made from and bark of the cedar tree cure scurvy?
The tea was high in Vitamin C, the missing nutrient.
How is red oak bark tea used for medicine?
There have been claims by those striken with cancer that red oak bark tea is a cure? There is no scientifc proof but stories in Georgia, kentucky and Tennessee are as old as sin regarding red oak bark tea and its curative properties for cancer
A flower or tree that starts with the letter q?
The cure for malaria is from quinine (not sure of spelling), which I believe comes from the bark of a tree by the same name.
How can a willow tree cure a headache?
The bark of the willow tree contains a substance called Salicylic acid from which the drug Aspirin is made. Aspirin is good for headaches.
Which rain forest tree helps in the treatment of malaria?
The cinchona tree, which is native to in the Amazon rain forest. This tree's bark is the source of quinine and is the original cure for malaria.
When was the first drug used?
Hard to answer specifically. Ancient Egyptians used herbs and teas to cure ailments. Native Americans chewed the bark of willow to cure headaches (aspirin) long before explorers arrived.
