Iris

There's a particular shade of blue that only irises do properly — a clear, cool, almost chalky blue that sits somewhere between cornflower and forget-me-not but is truly neither. Jane Phillips is my favourite example of it. She's a tall bearded iris, which means she has those wonderful velvety falls and upright standards that give irises their distinctive, slightly regal silhouette.

The colour is extraordinary in certain lights. On an overcast day she reads as a cool, silvery lavender. When the sun catches her, she's a pure, singing blue that makes everything around her look slightly muted. I've seen her stop people mid-conversation in the garden — they just pause and look, the way you do when something genuinely surprises you.

She flowers in May and June, which puts her right in the heart of that generous, luxurious window when the garden is at peak performance. I grow mine at the front of a sunny border where they can bake — irises like it hot and dry, which makes them brilliantly low-maintenance once established.

The flowers don't last long individually — each bloom maybe two or three days — but each stem carries several buds that open in succession, so you get a good ten days from a single stem. As a cut flower, one tall stem in a narrow vase is impossibly elegant. The silhouette alone is worth it.

I think irises are slightly undervalued in British gardens. Everyone fusses about with roses and then forgets that irises were here first, quietly being magnificent. Jane Phillips needs no fussing whatsoever. Give her sun, decent drainage, and a bit of space, and she'll reward you for years.