Dianella Coolvista An attractive, blue-grey, grass-like plant from Australia, Dianella revoluta Coolvista is a clump-forming, evergreen, rhizomatous perennial forming a spiky mound of narrow, sword-like, grey-blue leaves. In May and June, tall stems carry starry blue flowers above the clump of leaves; these are sometimes followed by blue berries. This plant is only borderline hardy, but can be grown in ericaceous soil-based compost in a pot taken under cover for the winter; it makes a lovely centrepiece for lower-growing, bright flowers. Must have fairly rich, acid-to-neutral soil. Site: ShelteredSoil: Any fertile, well-drained, humus-rich, neutral to acid soilPosition: Full sun or partial shadeSeason of interest: All year, midsummer in particularHardiness: Borderline hardy (to -5ºC)Height: 20” (50cm) Spread: 1’ (30cm)