Coneflowers are American flowers. They and their Lazy Susan cousins covered the continent at one time and have gained favor with gardeners as interest has grown in low-maintenance gardening with wildflowers. Because they are native plants, coneflowers, or Echinacea, are relatively pest and disease resistant when planted in habitats that resemble their original prairie homes. In the typical perennial border, however, they may need a bit of help when conditions allow a few insects and viruses to cause them to look less than their best.
Establish coneflowers in loamy, well-drained soil to encourage strong roots for well-developed, sturdy top growth.
Locate plants where they will get plenty of sun but will have afternoon shade during midsummer.
Space plants at least a foot apart for good air circulation. Move plants out from behind low-growing plants to get sun to lower branches and encourage root development.
Mulch coneflowers with about an inch of fresh, clean compost each spring to shade roots, discourage weeds and provide slow-release nitrogen for growth. Remove it each fall.
Deadhead blooms to prevent early seed formation. Pinch back branches to keep plants compact and encourage an extended season of bloom.
Plant coneflowers in full morning sun to discourage garden fleahoppers and other insects that wake up early to start looking for cool shaded plants.
Keep weeds pulled in the mulch around coneflowers to minimize the attraction for aphids and garden fleahoppers.
Clear out dead foliage and old mulch every fall to remove shelter for and kill eggs of aster leafhoppers and garden fleahoppers.
Remove and destroy foliage that appears withered or mottled. Both aphids and fleahoppers suck sap out of leaves and stems; garden fleahoppers may leave light or dark spots on affected leaves.
Use insecticidal soap for heavy infestations of aphids. Pesticides containing neem and natural pyrethrums are effective, and the systemic insecticide acephate works well on eggs and immature aphids.
Deadhead flowers and remove branches with blighted leaves affected by botrytis and other molds and fungi.
Use trickle irrigation instead of overhead watering to protect plants against septoria, cercospora, botrytis and other fungi and bacteria.
Dig out plants afflicted with aster yellows or chrysanthemum stunt, viral diseases that cause mosaic patterns on leaves and malformation or stunting of stems and growing shoots. The diseases are terminal and contagious.