Garden Detective: Getting rid of cottony scale
Jessica DamianoJessica Damiano
Jessica Damiano is a master gardener and journalist with more
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DEAR JESSICA: I saw these white spots on my blueberry bushes today. When I pulled one off, it had a red sticky center. I tried looking it up but couldn't find a similar picture. Not all of the bushes have this. What is it? -- Kathy Mosinka,Valley Stream
DEAR KATHY: It looks like your bush has cottony scale, an insect that covers itself and its attached egg sac in white fluff and feeds on the plant's sap. The red, sticky substance is actually a mass of 600-800 eggs. Left alone, scale can weaken plants and reduce yield.
Pick or rub them off by hand or with a toothbrush, and give your plant a nutritional boost in spring with a dose of fish meal, blood meal or feather meal.
DEAR JESSICA: Please let me know how to treat a gray powdery coating on several of my hydrangeas. They do not appear to be sick, but they look terrible. -- Brian Bretan, Fort Salonga
DEAR BRIAN: Powdery mildew is a disease that thrives in shade under humid conditions and commonly targets hydrangeas, covering leaves and branches with a powdery substance. It's seldom fatal to the plant but can lead to decline and, as you point out, is unsightly.
Thinning plants by removing crowded branches will help to increase air circulation throughout the plant, decreasing susceptibility to powdery mildew and other fungal diseases. Spraying healthy plants with one tablespoon of baking soda diluted in a gallon of water will work as a preventive, but to eradicate an already existing infection you'll get better results if you spray with a fungicide labeled for use against powdery mildew.
Be sure to clean up fallen leaves and other plant debri, and dispose of it all in the trash to prevent a reinfection next year.
DEAR JESSICA: For the past five years, I have taken my daughter's gardenia plants into the house for the winter. The plants are tremendous. Can they be trimmed before we bring them indoors? Also, can you suggest something to spray them with? They had a lot of yellow jackets around them, and I see small flies when I water them. I do not want to bring these into my house. I noticed some brown spots under the leaves and hope the spray takes care of that, too. I am lucky to keep them healthy over the winter. -- Anne Kuhlwilm, West Islip
DEAR ANNE: Some gardenias bloom on old wood, while others bloom on new growth. Without knowing which category your plants belong to, it's impossible to say whether pruning will impede next year's bloom cycle. However, cutting them back a bit to control their size shouldn't harm them.
The brown spots on the underside of your gardenia's leaves are likely scale insects. Scale secrete a sticky substance called honeydew after feeding on plant sap. And it's the honeydew that attracts yellow jackets (and ants). Rinse the plant with a strong spray from a garden hose to remove any other insects. Then, apply horticultural oil spray to remove the scale, taking care to coat the undersides of leaves.
Once indoors, gardenias will require regular watering, the most sunlight possible and a humid environment that isn't too warm. They won't likely bloom indoors but should remain healthy if those needs are met. Your plants also will benefit from applications of a slow-release azalea fertilizer, which will fortify them for another round of blooms next summer.
DEAR JESSICA: My geraniums did not grow as well as last year. This past weekend, I was pulling them out of my raised beds and noticed they still had their original pot size from when I planted them. They also pulled out of the soil very easily. Did I do something wrong? -- Scott Wojcik, Wantagh
DEAR SCOTT: It sounds like your plants were pot-bound before you planted them. This happens when plants outgrow their containers. There is no room for roots to spread out, so their growth encircles the root ball until it becomes a tight, tangled, pot-shaped mass.
Once that happens, even if replanted in loose soil, roots won't be able to stretch outward unless they're "teased," or loosened, to enable them to resume normal growth. This also explains why your plants failed to thrive: Their roots, whose job it is to bring water and nutrients to the plant, and anchor it into the soil, couldn't function properly.
It's always a good practice to slip plants gently out of their pots at the nursery before purchasing, so you can check the condition of the roots. But mildly to moderately pot-bound plants don't necessarily need to be avoided.
To tease the roots, scrape a pair of pruning shears or scissors around the outside of the rootball. Sometimes, I just snip inch-long sections all around; sometimes, I just pry the bottom of the root ball apart with my hands. Any of these methods will free the roots and stimulate them to grow outward into the surrounding soil.