Irises are a beautiful and elegant perennial flower that can bring a lot of beauty to your garden. However, they can also be vulnerable to pests and diseases, especially in Minnesota. To ensure that your iris plants stay healthy and vibrant, it's important to take the necessary steps to protect them from pests and diseases. The most common pest that affects irises is the iris borer.
These pests drill holes in the leaves of the iris plant in early April or May and continue to tunnel to the rhizome. Evidence of their presence includes leaves with tan stripes or soaked in water. To combat this pest, it's important to choose resistant varieties, identify damage early, and use insecticides or natural enemies. A neem foliar spray kills pests on contact and may combat some surface fungi.
You can also avoid digging from above by placing framed screens over the planting area until the ground freezes. Of course, the screens must be removed before spring emerges. Similarly, row covers can be used to exclude people who dig above the ground, such as squirrels and chipmunks. Don't forget to cover the containers and planters where you planted bulbs.The University of Minnesota Extension provides detailed instructions on how to identify iris borers when inspecting your plants in spring and summer.
The best way to control the iris borer is to remove and destroy old plant leaves and plant debris after a severe frost.Other diseases of the iris, such as bacterial soft rot, iris burn, and fungal leaf spot, may show similar symptoms even when iris borers are not present. Soft rot (Erwinia carotovora) affects the rhizomes of the iris that have been damaged and is often the result of damage from the iris borer. All types of irises can be attacked by the iris borer, but Siberian irises are more tolerant.To a certain extent, you can prevent future problems with iris borers by properly trimming and cleaning your iris plants in the fall. During periods of drought (longer than three or four weeks), you'll have to water them deeply every 3 or 4 weeks, depending on the temperature.You can also fertilize your irises in early spring, about 6 to 8 weeks before flowering and again after the flowers have disappeared.
If you're ready to bring the elegant perennial beauty of lilies to your garden, you can order many types of iris flowers online.By following these tips, you can ensure that your planted iris bulbs stay healthy and vibrant for years to come. Choose resistant varieties, identify damage early, use insecticides or natural enemies, cover containers and planters, inspect plants regularly for signs of pests or diseases, trim and clean plants in fall, water deeply during drought periods, and fertilize in early spring.