Perovskia; Russian Sage:
Perovskia is a plant that needs a ‘Chelsea Chop’ – which means you cut it back by half during the Chelsea Flower Show NO MATTER HOW NICE IT IS LOOKING IN MAY.
If you decide not to, it flowers then flops everywhere instead of standing a bit shorter but definitely more perkier. The plant has a lovely sage scent, but when you cut it it is a dusty plant and so you end up coughing or sneezing, it also can irritate sensitive skin slightly, so wear gloves.
Other than that it’s a lovely garden plant!