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Iris care

Christina Asked

I have invested several hundred dollars in my iris collection. I put them in a bed that I bought soil for that I thought would be good dirt for them. Problem is, it stays too wet, which I am working on to fix but in the mean time they got fungus. Its the leaf spot type. My problem is unless I spend lots of time trying to figure out which fungicide is best to use, I am not going to get the right one. I have already been looking with no results. I don’t have a lot of time to get this done. I hope you can help.

The Gardener’s Answer

Hi, Christina: The Iris genus is a large group of plants. Some varieties like wet feet but others prefer moist, but well-drained soil. What kind of Iris are you growing? Siberian Iris are tolerant of wet soil but tall bearded iris should not be planted in heavy, compacted soil. Iris leaf spot will not kill your plants, but it can decrease vigor if the disease is allowed to spread year after year. This fungus will overwinter on infected foliage so good sanitation is essential in preventing disease spread. Remove and discard all infected foliage as soon as you notice it. Iris leaf spot is more prevalent during cool and rainy weather. Overcrowding can also be a factor as it leads to poor circulation. Fungicides are generally not needed for Iris Leaf Spot in the home garden. In severe cases, fungicides are an option. Sprays will not correct the damage that has already occurred but can prevent future spread if used according to product recommendations. Drainage can be improved by incorporating organic matter into the soil. Contact your County Cooperative Extension Service if you are interested in having your soil tested.  Click here for specifics in terms of fungicides. This publication is provided by the University of Kentucky in collaboration with the Kentucky Cooperative Extension Service and other land grant universities. Publications provide reliable, research-based information for home gardeners.

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