Answer: Coneflowers (Echinacea purpurea) are naturally rather tall and leggy and young first year plants can be especially ungainly. (In any site receiving less than full sun, these plants will really stretch for light, too.) Unfortunately, in my experience, pinching doesn't really force them to fill out much. Instead, they fill in from the crown over time; by the end of this season your little plants should be quite thick at the base. Careful deadheading, though, will help them branch slightly as well as extend the bloom period. For a fuller look in the garden you might try planting several together at fairly tight spacing to form a "drift". Coneflowers are quite easy to divide and move, so you will be able to correct the spacing later if they begin to crowd.
Q&A Library Searching Tips