This next plant is moderately invasive. It has a long flowering period (midsummer to early fall) and the first flowers are setting seed before the last flowers have opened, so it is impossible to dead-head it without cutting off open flowers and flowers in bud. My advice is to be ruthless and give it a late-summer haircut, but I often don't follow my own advice and spend time pulling up seedlings next spring. The plant is Scabiosa columbaria 'Alpina', and the original plant I bought in 2004 is still going strong.
