The purple coneflower Echinacea purpurea is a common wildflower. This flower resembles a large daisy with purple petals and a large orange center, although there are different-colored cultivars. The purple coneflower is a very low-maintenance plant, but some common garden pests, as well as poor cultural practices, cause the usually upright flower stalks to wilt.
Common Stem Borer
The common stem borer will infest any plant stem wide enough and soft enough for it to chew through. It usually starts feeding at the plant’s base or from the whorl where the leaves emerge from the stem. Feeding from the whorl causes the plant to wilt, according to the University of Minnesota. Stem borers eat away at the stem’s insides until the plant dies. Cut back a wilting flower stem and check its insides for borers. If the damage is severe, destroy the plant and start again next year.
Sclerotinia blight is a plant disease that causes wilting then death of the purple coneflower. Signs of the disease include dark brown or black lesions at the soil line and just above. The roots are rotted and black. Moist conditions favor the disease’s development and can wipe out entire purple coneflower plantings. Rotate plantings if you know Sclerotinia blight is the cause of death. The government of Alberta recommends planting cover crops, such as barley or alfalfa, for a couple seasons before replanting purple coneflower in the same place.
Too Much Water
In the wild, purple coneflower prefers moist soil, but too much water leads to wilt. Once the root zone becomes saturated, plants cannot take up any more water or nutrients and wilt. Purple coneflower is a drought-tolerant, low-maintenance wildflower. Too much care is almost worse for the plant than is too little.
Too Little Water
While the plant is drought-tolerant, it does need some water. Too little water, especially if growing in a full-sun with little rainfall, leads to drought-stressed, wilting plants. In the absence of an average amount of rainfall, water plants about an inch every other week.