Positioning
The Big Sky series of Echinaceas are hybrids between E. paradoxa and E. purpurea species. Both are native to prairies and open woodlands so do best in full sun to part-shade. Too much shade will result in a significant decrease in the amount of flowers produced.

Soil
A well-drained fertile soil is favoured. These Echinaceas have good drought tolerance but shouldn't be neglected for watering, especially while young plants are establishing themselves. It's very important that plants are grown in a well-drained soil as the roots are likely to rot if soil is waterlogged.

A good amount of organic fertilizer applied in spring will encourage better growth and development. In poor soils an extra amount in summer might help to prolong flowering. If you are not using liquid fertilizer, make sure that it gets washed in, so that the roots can absorb it. 

Deadheading 
Removal of faded flowers before they set seed will encourage plants to keep producing new ones during the same season. Leaving flowers on the plant will result in its energy going into seed production.

Diseases
Echinacea has very little in the way of disease problems. Some leaf spots may occur, but these will not be lethal, and after dormancy the plant will emerge again with healthy leaves.

Links
Another website you might like to check for information on growing Echinacea is Perennial Flower Gardening.

What are your experiences growing Echinacea 'Twilght'? Got any questions or tips for your fellow gardeners?