Liatris spicata or Lampcleaner or Knotted Snake Root .
Liatris spicata is a beautiful border plant that produces spike-shaped flowers in summer. Spicata is Latin for 'ear formation'. It is originally a prairie plant. It is therefore a strong, hardy garden plant, but loses its leaves. When all the buds have appeared on the spikes, purple flowers begin to bloom at the top of the spike. This means that the Lamp Polisher has finished flowering first. The leaves are elongated and resemble grass. The flowers of the Liatris spicata can be used as cut flowers; they have a long shelf life. It is a garden plant that combines nicely with other flowering perennials due to its straight vertical shape. The Liatris spicata is popular with butterflies, bumblebees and bees.
I used to have some of these in my garden. I'm wondering if it's a biennial. I like this low POV so the flowers look tall and of course they are rather spiky.
Ian