Irises are some of the most beautiful flowers in the garden, with their large, intricate blooms in a variety of colors. Unfortunately, they can be vulnerable to pests and diseases, especially in Minnesota. To keep your iris plants healthy and blooming, it's important to know how to protect them from common pests and diseases. The most common pest of irises is the iris borer.
These moths lay their eggs on the leaves of the plant in early April or May, and when the larvae hatch, they tunnel into the rhizomes. Signs of an infestation include leaves with tan stripes or soaked in water. The best way to control iris borers is to remove and destroy old plant leaves and debris after a severe frost. Another way to protect your iris plants is to choose resistant varieties.
Siberian irises are more tolerant to the attack of the iris borer than other types of irises. Additionally, you can identify damage early by inspecting your plants regularly for signs of infestation. If you do find signs of an infestation, you can use insecticides or natural enemies to control the pests. Insecticides such as Funginex or Daconil can be used to treat infected plants.
For a more organic solution, baking soda and water can be used. Dissolve 1 teaspoon of baking soda in a liter of water, add a few drops of liquid soap to the mixture to help it stick better to the foliage, and spray infected plants thoroughly.Manure tea is another unusual remedy for fighting fungal diseases like black spots, mildew, and rust. Place a gallon of well-composted manure in a 5-gallon bucket and fill it with water. Stir the mixture thoroughly and let it sit in a warm place for three days.
Strain the mixture through gauze or mesh and use the resulting tea to spray plants affected by the disease (the remaining solids can be applied around the base of the plants as an added fertilizer).Finally, store your rhizomes in a cool, dark, dry place with constant temperatures between 40 and 50 °F. This will help prevent fungal diseases like leaf spot from taking hold.By following these steps, you can protect your iris flowers from pests and diseases in Minnesota. Choose resistant varieties, identify damage early, use insecticides or natural enemies when necessary, store rhizomes properly, and use organic solutions like baking soda or manure tea for fungal diseases.