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L ike insects, diseases can also ravage a garden. To manage disease, we have to rely on what we can and can- not influence. Here we focus on the plants themselves, the diseases and their life cycle and the environment. Again, start with healthy plants when you're buying new plants. Also choose plants that have higher disease resistance, such as specific tomatoes and peppers, mildew resistant phlox, bee balm or roses resistant to black spot, etc. We can help you pick these out. For your existing plants, we need to focus on plant health which includes put- ting the right plant in the right place again. The more shade you give a full sun plant, the more it stresses the plant. This increases its chance for disease. Another thing to avoid is putting drought tolerant pants or even those that require regular growing conditions, in wet areas or soils that drain slowly. Areas that remain wet for longer periods of time will increase your chance for disease. Diseases and moisture go hand in hand. Soils contain many disease spores and wet areas have a better chance of splash- ing soil up onto plants and thus spreading disease. If you have a wet area look for plants that like those conditions, like car- dinal flower or small ornamental willows. Also most shade plants don't mind a little excess moisture, one of the reasons they are considered shade plants. There aren't many plants that like dry shade, Epimedi- ums are one exception. Knowing the common diseases also helps avoid problems. Septoria and blights on tomatoes, powdery mildew on ninebarks, or cercospora leaf spot on hydrangeas are good examples. This may intimidate you but that is why we experts are here for you. The best way to culturally help avoid dis- eases is to disrupt their life cycle. We talked about moisture above. By control- ling any excess moisture, we can disrupt that part of a diseases life cycle. Many diseases are spread by bad insects like aphids or thrips so by controlling insects you can also disrupt the life cycle. Organic sprays like Neem oil coat the plants leaves, which prevent the disease spores to attach to the leaves. Anything we can do to disrupt this life cycle is benefi- cial. We also want to look at the environment. We talked a little about it above. There are some things we can influence and some we cannot, like the weather. Wetter years, which include high humid- ity, make disease control more of a chal- lenge, where drier years make it much eas- ier. We never want excess water sitting on, or around, our plants for long periods of time. One thing we can control is plant place- ment. Again, put the right plant in the right place. This is still the best way to avoid all problems. Air flow is crucial to help dry plants and soil quicker after a rain, watering or even in high humidity. Make sure you follow spacing guidelines for your plants. The more space between your plants, the better the air flow and the quicker the area dries out. Plants tucked in corners or blocked by fences or other things can also show prob- lems due to lack of air flow. So look at the area closely before you plant anything. One last thing, watering. Always try to water your plants in the morning so things can dry properly. You never want to water at night as this will allow water to remain on and around your plants longer, something we're trying to avoid. Follow these practices and you should have much better control of disease around your landscape and, remember, we're always here for your questions. Happy gardening! (Michael Timm is chief horticulturalist at Ebert's Greenhouse Village in Ixonia.) JUNE 2021 HOME 5 MICHAEL TIMM Controlling disease in the garden Cercospora leaf spot is seen on a hydrangea leaf. Learn to recognize blight on tomatoes and other plants. This ninebark plant has powdery mildew.

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